The benchmark Nikkei 225 index was down 0.45 percent, or 98.40 points, at 21,658.15. It grew 0.89 percent over the week.

The broader Topix index lost 0.40 percent, or 6.33 points, to 1,571.52, for a rise of 0.48 percent over the week.

"Profit taking weighed on the market ahead of the weekend," Okasan Online Securities said in a commentary.

The dollar fetched 108.62 yen in early Asian trade, against 108.66 yen in New York late Thursday.

Investors were somewhat cautious ahead of Japanese and US central banker meetings next week, Mizuho Securities said in a note.

In Tokyo, SoftBank Group climbed 1.08 percent to 5,665 yen after it announced a new $108 billion investment fund, the long-mooted successor to its blockbuster Vision Fund.

Nissan dropped 3.21 percent to 741 yen after announcing a plunge in quarterly net profit and the shedding of 12,500 jobs.

Toyota was down 0.98 percent to 7,151 yen and Honda fell 2.02 percent to 2,785.5 yen.

Chip-testing equipment maker Advantest edged down 0.12 percent to 4,155 yen after a 20.23 percent surge in the previous session, while chip-making equipment firm Tokyo Electron fell 1.37 percent to 18,295 yen.