The purpose of the present invention is to provide a valve mechanism which features a simple structure adapted to collectively control the supply of gas or culture medium to a plurality of cultivation containers for simultaneous cultivation and to enhance the reliability of the valve mechanism. The valve mechanism of the invention is a valve mechanism for opening and closing passages for liquid or gas. The valve mechanism includes: clip members adapted to close a plurality of tube passages, respectively； a multiple cam member for opening the clip members in sequence by making contact with the clip members； and a rotational mechanism for rotating the multiple cam member. The clip member includes: a spring for closing a clip thereof； and a clip contact portion for a cam contact portion of the multiple cam member to make contact therewith.
