A device with a connector comprising: a device including a through hole formed on an outer wall of the device, the through hole penetrating through the outer wall of the device and including a tapered opening, the tapered opening being an opening portion facing an outer side of the device that has an opening diameter larger on the outer side of the device than on an inner side of the device such that the opening diameter decreases toward the inner side of the device, and a waterproof connector, wherein the waterproof connector comprises: a connector body configured to be attached to the through hole by inserting a part of the connector body into the through hole, a sealing member having a ring shape and having a flexibility, the sealing member being configured to seal a space between an outer circumferential face (111b-1) of the connector body and an inner circumferential face (122b-1) of the tapered opening to provide waterproofness with respect to the through hole, wherein the sealing member includes a tube-shaped inner tube portion configured to closely contact with the outer circumferential face (111b-1) of the connector body, and an outer tube portion which surrounds the inner tube portion in a circumferential direction on a rear side intended to correspond to a rear side of an insertion direction when the outer tube portion is inserted into the tapered opening, which has an opening diameter larger than the inner tube portion, and which is formed integral with the inner tube portion on a front side intended to correspond to a front side of the insertion direction, wherein the connector body includes a holding projection, and the holding projection is configured to be inserted between the inner tube portion and the outer tube portion from the rear side in the insertion direction and is configured to push the outer tube portion against the inner circumferential face (122b-1) of the tapered opening when the sealing member is received between the outer circumferential face (111b-1) of the connector body and the inner circumferential face (122b-1) of the tapered opening, wherein the outer tube portion has a tapered-tube shape extending in a direction intended to correspond to the insertion direction with a taper angle (θ12) smaller than a taper angle (θ11) of the tapered opening such that an opening diameter of the outer tube portion decreases in the direction intended to correspond to the insertion direction, and the holding projection includes a face configured to face the inner circumferential face (122b-1) of the tapered opening with the outer tube portion sandwiched therebetween, the face being a tapered face (111h-1) extending in a direction intended to correspond to the insertion direction with a taper angle (θ13) larger than the taper angle (θ12) of the outer tube portion such that a diameter of the tapered face (111h-1) decreases in the direction intended to correspond to the insertion direction. a connector body configured to be attached to the through hole by inserting a part of the connector body into the through hole, a sealing member having a ring shape and having a flexibility, the sealing member being configured to seal a space between an outer circumferential face (111b-1) of the connector body and an inner circumferential face (122b-1) of the tapered opening to provide waterproofness with respect to the through hole, wherein the sealing member includes a tube-shaped inner tube portion configured to closely contact with the outer circumferential face (111b-1) of the connector body, and an outer tube portion which surrounds the inner tube portion in a circumferential direction on a rear side intended to correspond to a rear side of an insertion direction when the outer tube portion is inserted into the tapered opening, which has an opening diameter larger than the inner tube portion, and which is formed integral with the inner tube portion on a front side intended to correspond to a front side of the insertion direction, wherein the connector body includes a holding projection, and the holding projection is configured to be inserted between the inner tube portion and the outer tube portion from the rear side in the insertion direction and is configured to push the outer tube portion against the inner circumferential face (122b-1) of the tapered opening when the sealing member is received between the outer circumferential face (111b-1) of the connector body and the inner circumferential face (122b-1) of the tapered opening, wherein the outer tube portion has a tapered-tube shape extending in a direction intended to correspond to the insertion direction with a taper angle (θ12) smaller than a taper angle (θ11) of the tapered opening such that an opening diameter of the outer tube portion decreases in the direction intended to correspond to the insertion direction, and the holding projection includes a face configured to face the inner circumferential face (122b-1) of the tapered opening with the outer tube portion sandwiched therebetween, the face being a tapered face (111h-1) extending in a direction intended to correspond to the insertion direction with a taper angle (θ13) larger than the taper angle (θ12) of the outer tube portion such that a diameter of the tapered face (111h-1) decreases in the direction intended to correspond to the insertion direction.