A connecting structure for a joint member is constituted by a joint member formed from a metal material and having a hexagonal shape in cross section, which is inserted into a first port of a valve body made from a resin material. A U-shaped clip is inserted into a clip hole that confronts the first port and engages with a pin groove, which is formed on an outer peripheral surface of the joint member. In accordance therewith, axial displacement of the joint member accommodated within the first port is regulated. Further, rotational displacement of the joint member with respect to the first port, which also is formed with a hexagonal shape in cross section, is regulated while the joint member is connected with respect to the first port.