A wafer manufacturing method includes a wafer preparing step of preparing a wafer including a semiconductor device formed in each of a plurality of regions demarcated by a plurality of streets intersecting each other, a removing step of removing, from the wafer, a defective device region including a semiconductor device determined to be a defective product among a plurality of the semiconductor devices formed in the wafer, a support substrate fixing step of fixing the wafer to a support substrate, and a fitting step of fitting, into a removed region formed by removing the defective device region from the wafer, a device chip including a semiconductor device as a non-defective product having same functions as those of the semiconductor device determined to be a defective product and having a size capable of being fitted into the removed region, and fixing the device chip to the support substrate.