Provided is a locking plate system for treatment of a distal radius fracture including a locking plate (4) that is a flat laminate of intermediate molding materials that includes carbon fibers as a reinforcing material and thermoplastic resin as a matrix; a screw anchor (5) having a shaft portion (10) which has a principal thread (13) achieving a self-tapping action formed thereon and an outer circumference of a head portion of the screw anchor (5) which has an auxiliary thread (13) achieving a self-tapping action tapped thereon; and a through-hole (6) in the radius locking plate (4), which allows the radius main body (3) and the fractured bone piece (2) to be threadably fixed to the radius locking plate (4) and having a diameter that is oversized relative to the principal thread (11), and that is undersized relative to the auxiliary thread (13).