Disclosed herein are an injection foam molding apparatus for manufacturing one-piece shoes or soles and one-piece shoes manufactured using the same. A thermoplastic resin is injected into top and bottom molds in a state in which the top and bottom molds are coupled with a middle mold and is then pressed to form the upper and lower parts of a shoe, the middle mold is separated therefrom, and then the top mold and bottom mold, including the upper part and lower part of the shoe, respectively, are pressed, thereby forming the upper part and lower part of the shoe into one body. The injection foam molding apparatus is advantageous in that, since functional one-piece shoes or soles, having various colors, hardnesses and specific gravities, and having excellent feeling and durability, can be manufactured using different materials by one apparatus, working time is decreased, and productivity can be increased.