The government of El Salvador is "some considerable time away from ending the actual military fighting" against guerrillas here despite recent substantial increases in U.S. military aid, U.S. Ambassador Deane Hinton said today.

At the same time, Hinton said, the human rights situation that has been the principal criticism of those in the United States opposed to aiding the ruling civilian-military government, "is bad, and continues to be bad, but it's better than it was."

In his first interview since arriving here less than two months ago, Hinton painted a picture of the Salvadoran conflict that was somewhat less optimistic than that emanating from Washington in terms of progress on both the military and human rights fronts. But the overall thrust of his comments was along the same lines the Reagan administration has followed for the past several months -- the situation is not good, but it seems to be improving.

Hinton, 58, is probably the most prestigious U.S. ambassador ever appointed in Central America. With a background in Latin American affairs and intelligence within the State Department, he served five years as the U.S. ambassador to the European Economic Community and was assistant secretary of state for economic affairs before being named ambassador here.

It was not a job in high demand, and several career diplomats reportedly turned down what is considered to be one of the world's most dangerous embassies. But Hinton, a widower with 10 children and stepchildren in the care of relatives back home, has plunged into a busy schedule of lunches and dinners with as wide a spectrum of Salvadorans as possible.

He startles the security-conscious, including most of his staff, by appearing frequently in public places. Still, Hinton said, "The hardest part of the job is being a prisoner" within the cement-fortified embassy.

Sitting in his sandbagged office, puffing his pipe, Hinton stressed that he sees no essential differences between the Carter and Reagan administrations' policies of support for the ruling junta, on human rights or on military assistance to the government. But his conception of the job is clearly different from that of his predecessor.

Former ambassador Robert E. White delighted the press with his irrepressible talent for making news, and his relations with both the military and civilian sides of the government gradually evolved into a series of confrontations, primarily on the subject of military human rights abuses committed in the name of combating guerrillas.

Hinton is camera-shy, and seems averse to publicity in general. And the new ambassador tends to stress coordination rather than confrontation.

"Putting trainers" in El Salvador, Hinton said in a reference to the approximately 50 U.S. military advisers now training Salvadoran troops, "made perfectly clear the commitment of the U.S. government to see to it that the junta is not taken over by an armed insurrection supported from Havana, from Managua or anywhere else."

Human rights, the government's Achilles heel in terms of domestic and international support, is something Hinton is keenly aware of.

"No one would pretend the human rights situation is what it should be -- neither the military commanders I have talked to nor the civilian members of the junta."

Still, he said, "they are trying" to stop the large number of killings of noncombatants in the civil war that last year took an estimated 10,000 lives.

The "quiet diplomacy" advocated by the Reagan administration to deal with human rights problems marks the clearest break with the Carter past.

"I will continue to pursue human rights cases, particularly those involving American citizens, where we have a direct interest, but I will do it quietly, not planning any press conferences to denounce anything or anybody."

Principal among those cases involving Americans are the still-unsolved killings of four missionary women last December, in which six National Guard soldiers are being held, and of two U.S. agricultural workers in January, in which two prominent Salvadoran conservatives have been arrested.

But human rights will evidently take second place to what the new ambassador sees as the overwhelming priority of fighting communism.

"The extreme left is interested in taking power. That's why I call them Leninists instead of Marxists."