PURPOSE: To obtain a lightweight and high strength structure member which is used for a space structure body and has the self monitoring function for breakage.

CONSTITUTION: A constitution body member having at least two terminals 10a which can be connected with an outside lead wire 8 is formed from the fiber-reinforced composite material containing electric conductive long fibers 7, and an electric conductive circuit 7a is formed together with the lead wire 8 outside the structure body member through the terminal 10a. When the electric conductive long fiber is put into the electric conduction-disabled state, because of the breakage, etc., of the structure body member, the electric conductive circuit is cut, and the breakage of the structure body member can be confirmed on the ground through the monitoring of the electric conduction circuit.