In a container having a lid member coupled to a container body by a hinge, the lid member has a top panel, and an inner ring formed on the top panel, the inner ring being fitted to an inner peripheral surface of a sidewall of the container body in a closed state to seal the container body. The inner ring has an outer peripheral surface on which an outer peripheral surface projection is formed along a circumferential direction, and the container body has an inner peripheral surface on which an inner peripheral surface projection is formed along the circumferential direction, in the vicinity of an end portion of the sidewall. When closing the lid member, the outer peripheral surface projection contacts and slides over the inner peripheral surface projection to cause the lid member to be locked to the container body, with the inner ring sealing the container body.