The Pentagon had to lean on the Central Intelligence Agency and the National Security Agency earlier this year to get them to give Japanese police highly sensitive intelligence information for the criminal prosecution of Toshiba Machine Co. executives.

Defense Department officials were out for blood when they learned that in 1984 Toshiba had illegally sold super-sophisticated propeller-milling machinery to the Soviets. The $17 million sale enabled the Soviets to make virtually silent submarines, and will probably cost $30 billion to counteract.

We have reported on a secret Pentagon memorandum of last May, which gave details of "extensive confidential negotiations" between Pentagon and Japanese officials. The "satisfactory settlement" that resulted included a promise by Japan to tighten its export laws and supervisory system, punish Toshiba and C. Itoh, the trading company involved, and contribute unspecified but sizable sums to a joint research-and-development effort to overcome the Soviets' silent-sub advances.

The Pentagon negotiators wanted more, though -- specifically, criminal prosecution of the company executives involved in the Soviet sale. The secret memo makes clear how difficult it was to get the Japanese to agree to this, despite the substantial evidence implicating Toshiba's top brass.

"In Japan," the memo explains, "the police do not accept a case for investigation unless it is very strong. This practice has allowed the police to post a 90 percent conviction rate."

The memo adds: "The police have accepted the case."

Was this simply a Japanese government effort to assuage the wrath of the Pentagon -- and Congress -- over the Toshiba propeller-machinery sale? That may have entered into the Japanese decision, but the next paragraph in the memo gives a more solid inducement that was offered to the reluctant, conviction-conscious Japanese police:

"The police plan to seek an indictment but feel that their case is not airtight. The {U.S.} intelligence community, with prodding from {the Department of Defense}, is providing maximum assistance to {the government of Japan} to facilitate criminal prosecution."

This unusual cooperation of the CIA and NSA took some doing, according to Reagan administration sources. But it got results. In May, shortly after the memo was written, two top executives of Toshiba Machine Co. were arrested and charged with violating Japan's foreign exchange and trade control law. This law requires Japanese companies to abide by restrictions on high-technology trade with the Soviets imposed by the 16-nation Coordinating Committee for Export Control.

In addition, the Japanese government has amended its export law to increase the maximum prison sentence for future violators from three years to five, along with other stiff penalties. More important, the amendment will increase the statute of limitations from three years to five.