Google Inc. will relocate its Japan unit to the Mori Tower in Tokyo's Roppongi Hills complex where Goldman Sachs Group Inc. has its Japan headquarters.

Google Japan will move midyear from Cerulean Tower in Shibuya to accommodate its rising number of employees, said Yoshito Funabashi, a spokesman for the Internet giant in Tokyo.

Hideki Nomura, a spokesman for Roppongi Hills operator Mori Building Co., confirmed the agreement, though both spokesmen declined to elaborate on details of the accord.

Attracting Google as a tenant may be a victory for Mori Building as it seeks to increase occupancy in the 238-meter, 54-story Mori Tower.

Google will be among the biggest companies that pay rent to Japan's largest private real-estate developer, which is seeking to increase occupancy in Mori Tower. Google, which entered the Japanese market in 2001, has increased its staff over the years to take a larger slice of the market from Yahoo Japan Corp.

"They are likely moving to central Tokyo for the same rent they were paying in Shibuya," said Curtis Freeze, chairman of Honolulu-based Prospect Asset Management Inc. "It's a good sign that prices in central Tokyo are stabilizing."

Tokyo's office vacancy rate rose to a record level in February, according to Miki Shoji Co., a privately held office brokerage. Still, Tokyo replaced Hong Kong as the world's most expensive office location, after rents here declined at a slower pace, according to broker Cushman & Wakefield Inc.

Roppongi Hills has been attracting mainly foreign firms since the second half of last year, Nomura said. Recent tenants include Barclays PLC and Lenovo Group Ltd., China's biggest personal computer maker.