Despite increasing complaints from middle-income parents, the cost of sending a student to college isn't eating up any more of the family budget than it did in the mid-1960s. In fact, new figures show it's taking up less.

The statistics show that while college expenses have risen sharply in recent years - somewhat outpacing general living costs - median family income has climbed even faster, particulary for middle-class families.

The result: Rather than increasing, the percentage of median family income spent on college tuition and fees declined slightly between 1967 and 1976, the latest year for which figures are available.

The statistics are important because the notion that middle-income families have been pinched by rising college costs has been a primary factor behind the push for costly new aid for tuition and other educational expenses. These latest figures call that argument into question.

Here are the figures:

Total student charges, including tuition, fees, room and board, climbed sharply during those years - by 74.2 percent in the case of public colleges and 76.7 percent for private institutions.

At the same time, however, the median income of American families rose more rapidly, outstripping both the jump in college costs and the overall inflation rate.

The median income of all families rose 79.1 percent bwteen 1967 and 1976. And for families that had youngsters aged 18 to 24 attending college - mostly middle- and upper-middle-income families - median income soared by 87.3 percent, far more rapidly than college costs.

As a result, the proportion of family income spent on college costs declined during the nine-year period - by 2.3 percent for those attending public colleges and 1.1 percent, for those in private colleges.

In 1976, families whose youngsters attended private colleges spent 27.5 percent of their income on tuition, fees, room and board compared to 27.8 percent in 1967. For those in public colleges, the proportion declined to 13.1 percent from 13.4 percent in 1967.

The statistics, compiled by the Congressional Budget Office from figures collected by other government agencies, tend to undercut arguments by some special interest groups that more tuition aid is needed to offest the college "squeeze."

Congressional tax-writing committees have approved legislation that would provide costly new tax credits to parents of college students. The Senate panel's version would aid the parents of elementary and secondary school pupils as well.

President Carter has proposed a rival measure that would increase federal aid to college students to under write tuition costs for more middle-income families. The cost of these programs ranges from $1.3 billion to $4.5 billion a year.

Spokesmen for college groups concede the picture these figures portray is accurate, but insist that middle-income parents still are squeezed financially because rising costs of food and fuel have left them with less in "discretionary income" to spend on college.

Charles Saunders, legislative director for the Council on American Education, said his organization is urging opponents to "go beyond those figures" and "look at other uses of discretionary income." Saunders added, "You can't really say parents don't have a problem."

However, government economists who have been tracking the rise in living costs say while it's true that Americans are using more of their total income for fuel, that isn't the case for all expenditurea. For example, food costs are taking less of workers' paychecks now than in 1973-74.

The complaint that middle-income families are being "squeezed" by rising tuition costs has been a major element in the rationale for enacting larger tuition aid programs. Both the administration and proponents of the tuition tax credit have said it is valid.