The present invention sufficiently heats a repairing material while preventing change in quality of a base material provided with the repairing material so as to securely bond the repairing material to a repair target portion. The repair method of the present invention, in order to repair a repair target portion 14 existing in an outer panel 1, includes: a repairing material disposing step of disposing a repairing patch 21 including a resistance heating element 23 and a carbon fiber reinforced resin, and an adhesive 22A including a thermosetting resin before being hardened for bonding the repairing patch 21 on the repair target portion 14; and a heating-hardening step of heating and hardening the thermosetting resin of the adhesive 22A by causing the resistance heating element 23 to generate heat through supply of electricity thereto.