The Maryland State Senate yesterday unanimously approved "sunset" legislation, which requires that 60 different state agencies - from the powerful Racing Commission to the obscure Chiropratic Examiners Board - periodically prove to the legislature that they have not outlined their usefulness.

The measure must now face committee hearings in the House of Delegates, a body that traditionally has been cool to the idea of making major procedural reforms in the existing system of state government. Last year, a similar measure was killed by a House committee after receiving Senate approval.

Similar legislation is being considered by a Senate committee in the Virginia legislature.

The Maryland legislation, whose principal sponsor is Senate President Steny H. Hoyer (D-Prince George's), would give the various state agencies specified in the bill the burden of proving that they continued to perform a useful function.

At present, the legislator must show that an agency is not serving any useful purpose before a move can be made to end its existence. Such moves are also extremely rare - although the State Senate last week did approve and sent to the House a measure to dissolve the state's Bedding Advisory Board.

The concept of "sunset" legislation - providing for periodic review of governmental agencies - has been growing in popularity around the country since Colorado passed the first such measure two years ago. More than a dozen states now have similar measures designed to control or even reverse the expansionist tendencies of government.

House Speaker John Hanson Briscoe (D-St. Mary's) said yesterday afternoon that he wasn't sure how receptive the delegates would be to the "sunset" bill, which is being strongly pushed by the state offices of Common Cause, the citizens' lobby.

"I frankly haven't gotten a reading from the chairmen as to how much support there is for that particular concept," said Briscoe, who has assigned the sunset legislation to both the House Appropriations Committee and the Committee on Constitutional and Administrative law.

Briscoe added, "The appropriations people, I think, favor program evaluation," the so-called "zero-based budgeting" techniques that are also under scrutiny by many state and local governments.

The program evaluation concept, Briscoe said, actually goes further than the proposed sunset bill. Instead of dealing with relatively inexpensive and out-of-the-way boards and commissions, zero-based budgeting measures could result in the phasing out of programs run by such major state agencies as the transportation department.

The two concepts, however, are not incompatible, and Briscoe said it would be possible for the delegates to approve the sunset measure while continuing to study zero-based budgeting measures.

During a discussion of the "sunset" bill before the Virginia legislature yesterday, supporters said it should be known as something else because it does not provide for "terminating" government departments or agencies. The "Legislative Program Review and Evaluation Act," as the proposed legislation is called, would require the existing Joint Legislative Audit and Review Commission (JLARC) to schedule regular reviews of government agencies to consider simply whether they are needed or are fulfilling their intended function. The next move would then be up to the legislature.

Sen. Omer L. Hirst (D-Fairfax), who proposed the legislation, said it would impose a needed self-discipline on the existing review committee and help increase the use of government studies that are made now, but "sit collecting dust" because there is no systematic way to use them.

In an unusual switch, Hirst is opposed on this issue by majority leader Sen. Adelard L. Brault, his fellow longtime Democrat from Fairfax. Brault said during yesterday's hearing that the increased review capacity would make too much work for the part-time citizen legislature.