To provide a reinforcement structure for timber that improves the reinforcement strength of timber.

A reinforcement structure for timber includes an aramid fiber rod 10 of which one end is bent and a timber 20 with a hole 20a and a groove 20b extending from the hole 20a along the front face, and the one end is inserted into the hole 20a and the aramid fiber rod extending from the one end to the other end is fitted to the groove 20b.