To eliminate generation of fine difference in level and biting, etc. in a joint of flanks with each other of an outer peripheral cutting edge and a circular cutting edge of an end mill.

In this manufacturing method, the outer peripheral cutting edge and the flank of the circular cutting edge of the end mill are continuously machined by the same grinding tool. In a first process, a workpiece is inclined to a grinding wheel rotary axis at a crossing angle A with a turning axis as a center, and the flank of the outer peripheral cutting edge is machined by linearly moving the workpiece in a workpiece rotary axis direction relatively to the grinding wheel by moving of the workpiece. In a second process, the flank of the circular cutting edge is machined by circular arc moving of the workpiece based on the circular cutting edge on the same plane as that in the linear moving relatively to the grinding wheel.