Members of Congress profess to be "shocked."

Rep. John LeBoutillier (R-N.Y.), a firebrand young conservative, says it is "quite wrong."

A Queens businessman asserts that it will "perpetuate communism."

Yet as red as faces are all around, nobody in the U.S. government seems to be able to come up with a good reason why the American armed services should stop buying almost all their manual typewriters from communist East Germany, a leading military ally of the Soviet Union.

Since 1978, the East German-made Optima typewriters, the cheapest on the market, have been selling like hot cakes to the Pentagon. The General Services Administration, which coordinates procurement for government agencies, has bought some $5 million worth of the Optimas, with most going to the Army.

What is more, the Treasury Department approves of the East-West typewriter connection. It will provide the East German communist regime with more dollars to spend on American products, especially grain, the major U.S. export to that country.

In a statement last year, the department said it "would not be in our best interest to disqualify East German manufacturers from bidding on ordinary commercial items like manual typewriters, considering the excellent balance of trade in favor of the U.S. economy" as a result of grain sales.

And GSA administrator Gerald P. Carmen advised the House Appropriations defense subcommittee last Sept. 11 that "there is no legal basis for the GSA to refrain from contracting with foreign countries," including communist bloc nations.

The typewriter trade, though small in dollar amount, illustrates the ironies inherent in the Reagan administration's tough stance against the Soviet Union. The administration's fiscal 1983 budget calls for steep increases in defense spending.

Yet the United States and its European allies have a complex web of economic relationships with the Soviet bloc, to the point where the U.S. military is buying equipment made in Warsaw Pact nations.

The Optima typewriter, made by the East Berlin state enterprise Robotron, meets one important criterion of government agencies: it is cheap.

Optimas sell for $147.50, at least $60 below the Remingtons and Olivettis produced in Brazil and imported into the United States.

Except for small numbers made for export, the production of manual typewriters in the United States ended several years ago when most users converted to electric models. Manual typewriters are now made primarily in Brazil, East Germany, Poland, Hungary and Bulgaria.

Royal manuals, for example, are made in Hungary.

Optima is imported by International Typewriter Exchange of Chicago. For the last several years its competitor, the Morse Typewriter Co. of Queens, N.Y., has been fighting the Optima invasion in the halls of Congress and federal agencies.

However, trade laws and the Buy America Act provide protections only for American manufacturing companies facing competition from foreign imports, not for U.S. importers.

Morse vice president Arnold Morse told the House Appropriations defense subcommittee last July that products from state-controlled economies such as East Germany's sell at artificially low prices that destroy competition.

Morse charged that GSA and the Defense Department nevertheless "blindly" award business to the lowest bidder without considering the possibility that the purchases "perpetuate communism."

GSA bought only Optimas in 1978 and 1979 but told agenices to do their own purchasing in 1980. Many agencies stuck with Optima. Morse said Fort Irwin, Calif., bought 216 Optimas last June. He said Optima's success with the military has helped it sell thousands more to city governments and school boards.

Vice president Bill Nelson of International Typewriter Exchange said ITE has been selling 20,000 to 25,000 of the machines a year.

The Morse Co. is now challenging Optima on the ground that its type size does not meet government specifications. Nelson says that "the typewriters we've been furnishing for the last three years meet those specifications."

As if the Pentagon's dependence on East German typewriters was not concern enough, GSA's Carmen has advised Congress of another Pentagon connection to the Soviet bloc.

The government, he said, buys musical instruments made in Czechoslovakia for military bands.