PURPOSE: To provide a radial direction waveform spacer expander for reducing possibility of breaking in an abutment part.

CONSTITUTION: In a radial direction waveform spacer expander 1, a desired shape is obtained by punching a metal band-shaped unit worked into a waveform. Waveform work is performed so as to position a sagging part 1a in a tension side and a return part 1b in a compression side, of an abutment part, as viewed in a shear cut surface by punching work. Thus, in the sagging part, toughness is highly provided as compared with in the return part, and by positioning the sagging part in the tension side, a break in the abutment part is reduced.