WASHINGTON — The number of never-married women raising children on their own has increased sharply, and the women are doing poorly at getting child support, the Census Bureau said Wednesday.

In a biennial report cosponsored by the Department of Health and Human Services, the bureau said that in 1987 there were 2.6 million never-married women with children under 21 whose fathers were absent from the home. In 1985, the last previous count, the figure was 2 million.

The child support rate for these women was 20 percent, compared with a 74 percent rate for divorced or separated women.

Commenting on the report, Jo Anne B. Barnhart, assistant secretary of health and human services for family support, said, “We must never lose sight of the fact that both parents have an obligation to financially care for the children they bring into the world.”

Taken all in all, however, mothers of children with absent fathers were doing better at getting child support than in the previous count.

The bureau said support payments received by women with children under 21 in 1987 averaged $2,710, an increase of 16 percent over 1985 after adjusting for inflation.

The payments had decreased 12 per cent from 1983 to 1985.