A connector fitting structure includes a female connector without a rotating member and an elastic sealing part arranged on the female member. The female connector is configured so as to be engageable with a male connector having a guide groove formed for the rotating member. The male connector is provided with a fitting recess. The guide groove is formed on an outer circumferential face of the fitting recess. The male connector is configured so as to be engageable with another female connector with the rotating member for moving at least one of the male and female connectors in a fitting direction. The female connector includes a fitting protrusion for engagement with the fitting recess. The elastic sealing part is arranged on an outer circumferential face of the fitting protrusion to continuously adhere to an inner circumferential face of a fitting-side end portion of the fitting recess along the circumferential direction.