Induction heating method for shaft-like member having ribs and device thereof

The objective of the invention is to provide an one-time heating method capable of achieving superior yield and reducing current feed frequency to prevent cost increase, such that, even for a shaft-like member (10) with a varying axial diameter, uniform temperature increase can be easily adjusted. When the shaft-like member (10) are treated by induction heating, two feed sensors (21) along the axial direction and another feed sensor (22) along the circumferential direction for movable heating are provided simultaneously along the entire length of a heating region (17). The shaft-like member (10) is spun around its axis while high-frequency current is fed to sensors (21) and (22). Through the adjustment of the two systemized and independently operated axially directional sensors (21) relative to the core circular plane (11), and the adjustment of the circumferentially directional sensor (22) relative to the ribs (12), the invention can produce high-quality product at limited costs efficiently.