PURPOSE: To reduce the hollow diameter of a hollow shaft, and to obtain a compact and light hollow joint device, by directly providing a groove for a rolling body on the outer periphery of a through shaft and on the inner periphery of a hollow shaft, and inserting the rolling body therebetween.

CONSTITUTION: A groove for a rolling body 11 is directly provided on the outer periphery of a through shaft 8, and the groove for the rolling body 11 is directly provided on the inner periphery of the hollow shaft 10 becoming a pair with the through shaft 8 as well. Thus, the hollow diameter of the hollow shaft 10 can be reduced.