Abstract: There are provided a male type connector (1), a protective cap (2), an inner cap (3) that supports a disinfectant-impregnated member therein and is retained in the protective cap, and a female type connector (4) in which an inner cylinder is fixed at an end of an outer cylinder, the inner cylinder including an internal end portion located inside the outer cylinder and an exposed external end portion. The inner cap includes engaging legs at each of which an engaging convexity is formed. A front end portion of the male type connector allows the engaging convexities at the engaging legs to engage therewith from inside. An inner cap retaining portion is formed on an inner wall surface of the protective cap, and a force exerted by the engagement between the inner cap and the male type connector is larger than a force exerted by the inner cap retaining portion to retain the inner cap.