To provide a waterproofing method capable of performing waterproof treatment at low cost in a short period and maintaining waterproof performance unless a building is destroyed and a waterproof structure.

After an adhesive agent is applied to a concrete bed surface 1, a plurality of reformed asphalt sheets 4 are abutted on each other and adhered to each other. A tape 7 formed of a foam polyethylene is stuck on the abutted portion (joint part) of the reformed asphalt sheet 4 and a urethane coating material 8 is applied onto the reformed asphalt sheet 4 including the tape 7.