Functional underpants for men for securing air permeability and improving sexual health, the functional underpants comprising: 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 inserted between the outer cloth and the inner cloth of the penis support member having the double structure by sewing; and a rear member connected to a lower end of the scrotum support member having the single structure and to the left and right sides of the outer cloth of the front portion of the underpants by means of sewing, characterized in that a penis pocket and a scrotum pocket are generated, respectively, due to application of tension and contractile force to the penis support member and the scrotum support member while a wearer wears the functional underpants, by a first bending section, a second bending section, a third bending section, a first curved portion, and a second curved portion provided at the penis support member, the scrotum support member and the rear member, wherein the first bending section is formed by a first segment from the upper portion of the penis support member being cut in a vertical direction so as to be narrower than the first curved portion which has a predetermined curvature and the first segment being connected with the upper end of the first curved portion by sewing; the second bending section is formed by being cut to have the first curved portion which is connected to the first bending section and has the predetermined curvature such that the first curved portion of the penis support member form a parabola when being folded in half, and by being connected to an upper end of the scrotum support member by means of sewing; and the third bending section is formed by being cut to have a second curved portion which is connected to the second bending section and has a curvature that is larger than that of the first curved portion of the penis support member and by being connected to a lower end of the scrotum support member and a lower end of the rear member by means of sewing; and wherein the first bending section, the second bending section and the third bending section are cut and connected with each other by means of sewing and are symmetrical to each of the penis support member, the scrotum support member and the rear member with respect to a central line. 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 inserted between the outer cloth and the inner cloth of the penis support member having the double structure by sewing; and a rear member connected to a lower end of the scrotum support member having the single structure and to the left and right sides of the outer cloth of the front portion of the underpants by means of sewing, characterized in that a penis pocket and a scrotum pocket are generated, respectively, due to application of tension and contractile force to the penis support member and the scrotum support member while a wearer wears the functional underpants, by a first bending section, a second bending section, a third bending section, a first curved portion, and a second curved portion provided at the penis support member, the scrotum support member and the rear member, wherein the first bending section is formed by a first segment from the upper portion of the penis support member being cut in a vertical direction so as to be narrower than the first curved portion which has a predetermined curvature and the first segment being connected with the upper end of the first curved portion by sewing; the second bending section is formed by being cut to have the first curved portion which is connected to the first bending section and has the predetermined curvature such that the first curved portion of the penis support member form a parabola when being folded in half, and by being connected to an upper end of the scrotum support member by means of sewing; and the third bending section is formed by being cut to have a second curved portion which is connected to the second bending section and has a curvature that is larger than that of the first curved portion of the penis support member and by being connected to a lower end of the scrotum support member and a lower end of the rear member by means of sewing; and wherein the first bending section, the second bending section and the third bending section are cut and connected with each other by means of sewing and are symmetrical to each of the penis support member, the scrotum support member and the rear member with respect to a central line.