BONN, JAN. 16 -- When Soviet Foreign Minister Eduard Shevardnadze arrives here Sunday for an official visit, he will find a country that is perhaps the most enthusiastic in the West about his boss Mikhail Gorbachev's new approach in foreign policy.

West Germany, at the front line of the East-West conflict and always yearning for better relations with communist East Germany, feels that it has the most to gain in the western alliance from what is viewed here as an emerging new era of detente.

The East-West thaw, highlighted by last month's signing of the U.S.-Soviet intermediate-range nuclear forces (INF) treaty, is contributing to major shifts in domestic politics. Conservatives who built careers on hostility to communism suddenly are competing to see who can be the most outspoken supporter of peace and disarmament.

Veteran right-wing leader Franz Josef Strauss surprised the nation last month by visiting Moscow, praising Gorbachev and proclaiming, "The postwar period is over. . . . A new era has begun."

The opposition left-of-center Social Democrats have had their foreign policy plucked away by the government. After spending most of the last six years arguing that Chancellor Helmut Kohl was too conservative to make peace with the East Bloc, the Social Democrats are looking for ways to jump on the detente bandwagon.

"The political spectrum has narrowed" on foreign policy, a government expert said. "For our politicians here, the best bet at every turn of the road is to say they want the {detente} process to continue," he said.

Kohl's center-right coalition has launched an all-out diplomatic offensive for better relations with Moscow and the Soviets' Eastern European satellites. During Shevardnadze's two-day visit here, the first in five years by a Soviet foreign minister, Kohl will press hard for a Gorbachev visit later this year.

West Germany's new attitude springs primarily from two sources: the perception that the threat posed by the Soviet Union has diminished under Gorbachev, and the flowering of a consensus that West Germany should forcefully assert its special interest in a less confrontational East-West climate.

Germans have a unique desire for detente because it is seen as the best route to overcome the division of their nation, and because European reconciliation helps assuage their feeling of responsibility for having started World War II, West German and foreign analysts said.

"This is a country that wants very deeply to live in harmony. He {Gorbachev} gives us the opportunity to heal the wounds," said Fred Oldenburg, a senior analyst at the Federal Institute for Eastern and International Studies in Cologne.

The current East-West thaw "gives us a chance to overcome our guilty feelings {from the war} and to solve the problem of German division," he said.

West Germany already has reaped one major benefit in inter-German relations from the improved climate, the landmark visit to Bonn in September by East German chief of state Erich Honecker. The Soviets had vetoed such a visit on at least two occasions to punish Bonn for its support for deployment of the U.S. medium-range missiles that now are to be removed under the INF treaty.

Opinion polls consistently have shown that most West Germans believe that Gorbachev is more interested in peace than is President Reagan.

Analysts caution that the public has reacted so favorably to Gorbachev in part because it historically had such low expectations for Soviet leaders. In addition, Reagan still suffers from his image in the early years of his administration as an unreconstructed Cold Warrior who described the Soviet Union as an "evil empire."

Nevertheless, Gorbachev's policies -- ranging from significant concessions in the INF negotiations to his expressed desire to withdraw troops from Afghanistan -- have caused a genuine reappraisal. Strauss said that the West no longer needed to fear that the Soviets had "offensive, aggressive intentions."

Public opinion has manifested itself most clearly on the issue in a string of election gains in the past year for the Free Democrats, the moderate junior partner in Kohl's coalition. The party's best-known leader is Foreign Minister Hans-Dietrich Genscher, who has played a key role in crafting the pro-detente policy.

The trend has fueled longstanding anxieties among West Germany's allies that the Soviets might succeed in their postwar objective of weakening West Germany's ties to the rest of the western alliance.

Already Bonn's enthusiasm for disarmament is irritating other leading members of the North Atlantic Treaty Organization. West Germany is pushing significantly harder than its allies for progress toward cutting arsenals of chemical arms and of battlefield nuclear weapons, or those with a range of less than 300 miles.

West Germany's stance results directly from its geographical position. Chemical arms and battlefield-range nuclear weapons most likely would be used on German soil, the principal East-West battleground, if World War III erupted, in the view of many analysts.

But it is much too early to say that West Germany is in serious danger of drifting toward neutralism, according to German and foreign analysts. The Kohl government feels that it can safely push for better relations with the East in large part because it feels confident of its good relations with America, they say.

Kohl acknowledged at a news conference on Monday that it was important to allay the "concern" of NATO partners that his government was traveling a "special German route."

Moreover, the Bonn government's positions on disarmament still are significantly different from Moscow's. The change is in the West Germans' efforts to go out of their way to publicize areas of agreement with the Eastern Bloc.

For example, senior conservative politician Alfred Dregger raised eyebrows at the start of the year when he quickly welcomed a proposal by Honecker for negotiations aimed at reducing battlefield-range nuclear arsenals. Dregger, chairman of the Christian Democratic-Christian Social Union caucus in the Bundestag, the lower chamber of the West German Parliament, is one of Bonn's most prominent hawks on security policy.

Dregger clearly designed his statement to cast himself as a supporter of arms control and of cooperation with East Germany. But he neglected to mention in the statement that he, like the government, completely rejects Honecker's proposal to bar nuclear weapons altogether in the two Germanys.

One of the more ironic twists in the German domestic debate is Kohl's appropriation of Ostpolitik, or West Germany's policy of rapprochement with the East, which usually is identified with the Social Democratic-led governments of the early 1970s.

Kohl's party bitterly criticized the Social Democrats when they carried out the policy. Now the government is hoping for rapid improvements in relations with the entire Eastern Bloc, and Genscher made a long-awaited visit to Poland this week.