PURPOSE: To calk a pinion shaft to a carrier without dislocation in the axial direction by forming open holes through which respective calking punches are penetrated in a first and a second receiving member.

CONSTITUTION: The respective end sections of a pinion shaft 5 are calked by calking punches 10a and 11a, so that they are fixed onto respective side plates 2 and 3 wherein the respective end sections are faced to each other while a planetary pinion is held, and the pinion shaft is inserted so as to be provided across the paired side plates 2 and 3 of a planetary carrier 1. In this case, the respective end sections of the pinion shaft 5 are firmly held in the axial direction against the respective side plates 2 and 3 by receiving members 22 and 23 which are brought into contact with the respective end sections of the pinion shaft. The respective calking punches 10a and 11a are brought into contact with the respective end sections of the pinion shaft 5 while being penetrated through open holes 22a and 23a formed on the respective receiving members 22 and 23, so that the respective end sections are thereby calked.