An optical connector includes a ferrule, a ferrule retaining member having, at its rear end portion, a fastening portion into which an optical fiber is inserted and onto which a tightening ring configured to hold a tensile strength wire and a jacket in place is tightly fastened, a housing, and a fiber insertion passage formed through the fastening portion. The fiber insertion passage has an expansion space that ensures an interference avoidance gap with an outer circumference of the optical fiber inserted inside the fastening portion.