Disclosed is a boot shape keeper capable of holding a boot in a fixed shape, removing malodor from the insole of the boot by allowing the insole of the boot to be opened to outside air while the boot is held. The boot shape keeper 1, which is inserted into a shaft part 21 of a boot to keep a shape of the shaft part 21 of a boot, includes a cylindrical body part 30 made by forming a plastic sheet 10 having a gas pre-encapsulated into a cylindrical shape, and a through hole 42b provided at a lower portion of a side wall surface of the body part 30, or a groove portion formed at a lower end of the side wall of the body part 30, wherein the body part 30 has a fixed shape provided by the encapsulated gas.