The Soviet Union moved the ruble into the electronic age this week as the nation's largest bank began issuing Visa cards to replace the passbook savings account, Visa International reported Friday.

"This is a giant step forward," said Charles T. Russell, president of Visa International, which is licensing Sberbank in Moscow to use the Visa name. Visa International, with nearly 200 million cardholders worldwide, is owned and operated by 21,000 banks.Russell said the move is the Soviet Union's first step toward automating its national banking system, with the aim for this year of extending the card to more than 40,000 customers and to 5 million within three years.

Sberbank, the nation's only retail bank, said it had begun issuing cards to a select group of 2,000 customers who will be able to use them to withdraw up to 250 rubles a week from automated teller machines, Russell said.

Foreign Visa cards have been accepted in the Soviet Union since 1974 through an arrangement with Intourist, which acted as an agent of the Bank of America's Visa card operation. Last year, Intourist itself became a Visa member, issuing its own internationally valid payment cards.

The Sperbank Visa card is to replace the traditional savings account passbook, serving as a debit card enabling the holder to get to funds on deposit.

Visa International spokesman David Brancoli said at VI headquarters in San Mateo that in the next six months service additions will include use of the card to make purchases at Moscow department stores and restaurants, with a few selected shops equipped with electronic point-of-sale terminals.