To provide a waterproofing method for a concrete structure, which bonds a waterproof sheet to a concrete surface to maintain complete sealing performance on the concrete surface, and can shorten a period of time required for sealing work, by sticking the waterproof sheet to a form internal surface which makes contact with concrete, and removing the form after pouring the concrete.

According to the waterproofing method, concrete 4 is placed on the internal surface of the concrete form 1 having the waterproof sheet 2 attached thereto, and the form 1 is removed after hardening of the concrete 4. Thus, the waterproof sheet 2 is bonded to the surface of the concrete 4 and a waterproof layer is formed on the concrete 4.