To facilitate operation connecting a gas container to a gas appliance.

A cam surface 26 changed in a diametric direction is formed in a periphery of a connection mate 20, a rotary member 40 is rotatably provided in the periphery of this connection mate 20, an engaging member 30, rotated into contact with the cam surface 26 to be made movable in a diametric direction, is provided inside the rotary member 40, a gas container 10 is engaged with the rotary member 40, by rotating the container pressed to the connection mate 20, and the engaging member 30 is locked to inside a mouth part 14.