PURPOSE: To form the crowning with high precision in a short time by preliminarily forming an initial crowning part of approximate dimensions by the tumbler working, and finishing this initial crowning part to the final crowning by the super-high finishing.

CONSTITUTION: In the tumbler process, a cylindrical roller stock 1 of a cylindrical roller bearing and abrasive materials are placed and rotated in a tumbler for several hours to form an initial crowning part Co. at each end of the cylindrical roller stock 1. The initial crowning part Co is in the condition of approximate dimensions before the final crowning, and most of the required crowning is removed in the tumbler process. When the tumbler process is completed, the super-high process is executed. The super-high process is the process to finish the initial crowning part Co. to the final crowning. The initial crowning part Co is finished first by a super-high finishing machine, and then, an outer diameter part 1a is finished.