A waterproof structure of a connector 1 is configured to waterproof a cable 40 including a sheath 41 surrounding a plurality of wires 42, and a connector housing 10 connected to the plurality of wires 42 extending from a tip portion 41E of the sheath 41. The waterproof structure includes a seal member 50 collectively covering the plurality of wires 42 between the cable 40 and the connector housing 10. The seal member 50 has one end fitted onto the sheath 41 and in which the plurality of wires 42 extend from the tip portion 41E with any arrangement relation, and another end fitted into the connector housing 10.