To provide a method for manufacturing a camshaft with bearings, by which an outer circumferential form of a cam piece in the camshaft with a bearing can be improved in precision and besides ground dusts can be prevented from entering the bearings of the camshaft with bearings.

There is provided the method for manufacturing the camshaft W with bearings, into which a plurality of cam pieces CA and a plurality of bearings BR are fitted in an axial direction of an outer surface of a shaft ST. The method includes a step of fitting a plurality of the cam pieces CA and a plurality of the bearings BR into each given position in the axial direction of the shaft ST to assemble the camshaft W with bearings and a step of finishing and grinding a grinding target cam piece by using a processing tool after having masked at least a bearing BR located nearest to a cam piece CA to be ground.