A molding method of a waterproof member (25, 27), wherein the waterproof member (25, 27) is molded by a pair of molds (51, 61) and is configured to surround a part of a coated electric wire in an extending direction of the coated electric wire in which the coated electric wire extends, wherein the pair of molds (51, 61) includes a first mold and a second mold having a first mold division surface and a second mold division surface, respectively, wherein the first mold division surface includes: a first molding portion (55a, 55b); and a first electric wire mold clamping portion and the second mold division surface includes: a second molding portion (65a, 65b); and a second electric wire mold clamping portion, wherein the first and second molding portions (55a, 55b, 65a, 65b) are configured to mold the waterproof member (25, 27) when the waterproof member (25, 27) is inj ection-molded, wherein the first and second electric wire mold clamping portions (52, 62) are configured to, when the first mold is attached to the second mold with the coated electric wire being disposed between the first and second molds, sandwich the coated electric wire at both sides of each of the first and second molding portions (55a, 55b, 65a, 65b) in the extending direction of the coated electric wire, characterized in that the first electric wire mold clamping portion includes: a first convex portion having a first semi-cylindrical concave surface configured to contact an outer peripheral surface of the coated electric wire; and a side wall erected on an end of the first convex portion in the extending direction of the coated electric wire, the end being connected to the first molding portion (55a, 55b), wherein the second electric wire mold clamping portion includes: a first concave portion including a second semi-cylindrical concave surface configured to contact the outer peripheral surface of the coated electric wire while being opposed to the first convex portion, the first concave portion having a U-shaped cross section; wherein the second molding portion (65a, 65b) includes a side wall entering groove formed by cutting out a part of the second molding portion (65a, 65b), the side wall entering groove being configured such that, when the first mold is attached to the second mold, the side wall enters the side wall entering groove, the method comprising: molding the waterproof member (25, 27) accommodated in the first concave portion with the waterproof member (25, 27) being pressed by the first convex portion toward a first direction in which the first mold is attached to the second mold. wherein the waterproof member (25, 27) is molded by a pair of molds (51, 61) and is configured to surround a part of a coated electric wire in an extending direction of the coated electric wire in which the coated electric wire extends, wherein the pair of molds (51, 61) includes a first mold and a second mold having a first mold division surface and a second mold division surface, respectively, wherein the first mold division surface includes: a first molding portion (55a, 55b); and a first electric wire mold clamping portion and the second mold division surface includes: a second molding portion (65a, 65b); and a second electric wire mold clamping portion, wherein the first and second molding portions (55a, 55b, 65a, 65b) are configured to mold the waterproof member (25, 27) when the waterproof member (25, 27) is inj ection-molded, wherein the first and second electric wire mold clamping portions (52, 62) are configured to, when the first mold is attached to the second mold with the coated electric wire being disposed between the first and second molds, sandwich the coated electric wire at both sides of each of the first and second molding portions (55a, 55b, 65a, 65b) in the extending direction of the coated electric wire, characterized in that the first electric wire mold clamping portion includes: a first convex portion having a first semi-cylindrical concave surface configured to contact an outer peripheral surface of the coated electric wire; and a side wall erected on an end of the first convex portion in the extending direction of the coated electric wire, the end being connected to the first molding portion (55a, 55b), wherein the second electric wire mold clamping portion includes: a first concave portion including a second semi-cylindrical concave surface configured to contact the outer peripheral surface of the coated electric wire while being opposed to the first convex portion, the first concave portion having a U-shaped cross section; wherein the second molding portion (65a, 65b) includes a side wall entering groove formed by cutting out a part of the second molding portion (65a, 65b), the side wall entering groove being configured such that, when the first mold is attached to the second mold, the side wall enters the side wall entering groove, the method comprising: molding the waterproof member (25, 27) accommodated in the first concave portion with the waterproof member (25, 27) being pressed by the first convex portion toward a first direction in which the first mold is attached to the second mold.