A waterproofing structure for a connector includes a first housing having a first terminal reception chamber for receiving a terminal and a second housing having a second terminal reception chamber for receiving a terminal. An opening end of the first terminal reception chamber is opposed to an opening end of the second terminal reception chamber, so that a gap with which circumferential edges of the opening ends are opposed to each other is configured to be sealed. An annular member made of resin is provided at the circumferential edge of the opening end of the first terminal reception chamber, the annular member having an inner circumferential surface widened toward the second housing. The circumferential edge of the opening end of the second terminal reception chamber abuts against the inner circumferential surface of the annular member.