A cryotrap which is set in a vacuum vessel, and has an exhaust panel which condenses and exhausts a gas by cooling, and a cooling stage which is connected to a refrigerator and thereby cooled, includes a cooling storage body fixed on a cooling stage while maintaining thermal contact with it, and a mechanism which thermally connects/disconnects the cooling storage body 6 and the exhaust panel. The mechanism which performs thermal connection/disconnection has a movable unit which has a good heat conductivity and can come into contact with and separate from the exhaust panel and the cooling storage body.