Functional underpants comprise a penis support member having a double structure comprising an outer cloth and an inner cloth, a scrotum support member having a single structure and being formed vertically under and connected to the penis support member, and a rear member connected to a lower end of the scrotum support member having the single structure. The outer cloth of the penis support member includes a first bending section, a second bending section having a horizontal length and formed under the first bending section, and a first curved portion formed between the first and second bending sections, which create a penis pocket along with the inner cloth of the penis support member. The scrotum support member includes the second bending section, a third bending section, and a second curved portion formed between the second and third bending sections, which form a scrotum pocket.