To provide a waterproof construction method for a basement and the waterproof structure of the basement, by which the infiltration of moisture from an underground section to the basement can be prevented particularly.

A water sealing material 4 is interposed among the lower frame A of a caisson C and both internal and external panels 3, 7 erected at a proper interval on the inside and the outside on the lower frame A, and the infiltration of water into the caisson C from soil through a section between the external panel 7 and the lower frame A is prevented while the infiltration of water into the basement from the inside of the caisson C through a section between the internal panel 3 and the lower frame A is prevented. The water sealing material 4 is interposed between the caisson C and basement base concrete 108, and infiltration into the basement of water in a ground through a section between the caisson C and basement base concrete 108 is prevented.