A waterproof connector which is attached to a wiring substrate, comprising: a pair of retainers (50, 60) between which the wiring substrate is interposed and which include an inner receiving portion formed on opposite surfaces (51, 61) which face the wiring substrate; and a first seal member which is made of a hot-melt seal material and is filled in at least the inner receiving portion, wherein an outer receiving portion in which the first seal member is received is formed on outer surfaces (55, 65) and side surfaces (50d, 50e, 60d, 60e) among surfaces of the pair of retainers which are along an inserting/separating direction of the waterproof connector, whereby the outer sufaces (55, 65) are opposite to the opposite surfaces (51, 61), and whereby the side surfaces (50d, 50e, 60d, 60e) cross the opposite surfaces (51, 61) and the outer surfaces (55, 65), a defective portion, which passes from the outer surface to the inner receiving portion and in which the first seal member is filled, is formed in at least one of the retainers, the inner receiving portion communicating with the outer receiving portion at the side surfaces (50d, 50e, 60d, 60e), the defective portion including at least one of an opening or a cutout, the first seal member including: an inner seal portion which is received in the inner receiving portion; and a connecting seal portion (70c, 70d) which is received in the defective portion and the outer receiving portion positioned on the side surfaces of the retainers and is formed integrally with the inner seal portion, and the connecting seal portion reaches the outer surfaces (55, 65) of the retainers, characterized in that the defective portion is formed over the entire overlap between the outer receiving portion and the inner receiving portion in an inserting/separating direction of the waterproof connector, and a surface area of the defective portion in a plan view is larger than a surface area of a portion of the overlap in which the defective portion is not formed. a pair of retainers (50, 60) between which the wiring substrate is interposed and which include an inner receiving portion formed on opposite surfaces (51, 61) which face the wiring substrate; and a first seal member which is made of a hot-melt seal material and is filled in at least the inner receiving portion, wherein an outer receiving portion in which the first seal member is received is formed on outer surfaces (55, 65) and side surfaces (50d, 50e, 60d, 60e) among surfaces of the pair of retainers which are along an inserting/separating direction of the waterproof connector, whereby the outer sufaces (55, 65) are opposite to the opposite surfaces (51, 61), and whereby the side surfaces (50d, 50e, 60d, 60e) cross the opposite surfaces (51, 61) and the outer surfaces (55, 65), a defective portion, which passes from the outer surface to the inner receiving portion and in which the first seal member is filled, is formed in at least one of the retainers, the inner receiving portion communicating with the outer receiving portion at the side surfaces (50d, 50e, 60d, 60e), the defective portion including at least one of an opening or a cutout, the first seal member including: an inner seal portion which is received in the inner receiving portion; and a connecting seal portion (70c, 70d) which is received in the defective portion and the outer receiving portion positioned on the side surfaces of the retainers and is formed integrally with the inner seal portion, and the connecting seal portion reaches the outer surfaces (55, 65) of the retainers, characterized in that the defective portion is formed over the entire overlap between the outer receiving portion and the inner receiving portion in an inserting/separating direction of the waterproof connector, and a surface area of the defective portion in a plan view is larger than a surface area of a portion of the overlap in which the defective portion is not formed. an inner seal portion which is received in the inner receiving portion; and a connecting seal portion (70c, 70d) which is received in the defective portion and the outer receiving portion positioned on the side surfaces of the retainers and is formed integrally with the inner seal portion, and the connecting seal portion reaches the outer surfaces (55, 65) of the retainers, characterized in that the defective portion is formed over the entire overlap between the outer receiving portion and the inner receiving portion in an inserting/separating direction of the waterproof connector, and a surface area of the defective portion in a plan view is larger than a surface area of a portion of the overlap in which the defective portion is not formed.