The preliminary Markit/Nikkei manufacturing Purchasing Managers' Index (PMI) for Japan climbed to 52.5 in October from 51.0 in September, beating expectations for a decline to 50.6.
A reading below 50 indicates contraction of activity.
The index was partly driven by a rise in output and new orders.
"Latest survey data indicated a marked improvement in operating conditions at Japanese manufacturers. Production increased at the joint-sharpest rate since February and was marked in the context of historical data," economist at Markit, Amy Brownbill, said.