A connecting part for ensuring a secure connection includes first connecting terminals that are arranged on one face of a supporting member and second connecting terminals that are arranged on the back face of the supporting member. The supporting member may have an elastic body. The connecting terminals are interconnected by conductive films which are formed on the face of the supporting member. Connecting parts are arranged between circuit boards on which electronic parts are mounted, and the circuit boards are mutually fixed in the state in which the connecting parts are compressed. The first and second connecting terminals are pushed against lands on the circuit boards by restoring force of the connecting parts, and then the circuit boards are electrically interconnected.