To provide an eccentric member mounting structure in a massage machine easy to assemble and capable of reducing cost by reducing the number of component parts.

The eccentric member mounting structure 100 is a structure in which an eccentric member 120 is rotatably mounted at an eccentric position relative to a rotary shaft 110. The eccentric member comprises a pair of circular collars 121a, 121b inserted into the rotary shaft and a bearing 130 mounted on the collars. The collars form shaft inserting holes 122a, 122b inserted into the rotary shaft at the eccentric position in the combined state, and also form bolt inserting holes 123a, 123b which penetrate through the pair of collars. Bearing fitting grooves 124a, 124b are formed on the outer peripheral face of the collar. A pin inserting hole 125 in the direction to the rotary shaft is formed on at least one of the pair of collars. A pin connecting hole 111 connected to the pin inserting hole is formed on the rotary shaft.