Thermal processing method, outer connecting member, and tripod-type constant velocity universal joint

Provided is a thermal processing method with which an outer connecting member of a tripod-type constant velocity universal joint can be formed having excellent strength by continuous high-frequency hardening without forming a hardened layer at the large-inner-diameter part. Also provided are an outer connecting member and a tripod-type constant velocity universal joint formed with a thermal processing method of this type. This thermal processing method is for the purpose of forming a hardened layer (S) on the roller guide surfaces (27) of an outer connecting member (21) by continuous hardening, whereby a high-frequency induction heating coil (51) is moved axially with respect to the outer connecting member (21), on the inner circumference of which track grooves (26), comprising the roller guide surfaces (27) which face each other in the circumferential direction and a large-inner-diameter part (46) provided between the roller guide surfaces (27), are formed in three locations. Magnetic-line-blocking bodies (A