Processing apparatus and processing method

A method of processing a crowned portion of a roller, which method comprises a step of:

• disposing first and second feed drums so as to extend parallel to each other, each of the first and second feed drums having an outer periphery formed with respective spirally extending threaded guide surfaces, the first and second feed drums being driven to rotate about respective central axes to transport the roller, while the roller is held in rolling contact with the threaded guide surfaces opposed to each other, from a first location towards a second location through between the first and second feed drums, and successively processing the crowned portion of the roller passing through between the first and second feed drums, by means of a through feed processing with the use of a grinding stone;
• in which the threaded guide surface of one of the first and second feed drums is formed so that an angle of inclination of an outer peripheral surface of the roller relative to a processing surface of the grinding stone is varied in dependence on a roller passing position of the feed drum.