The present invention provides a vacuum chamber capable of simplifying the structure of the arrangement of a cooling passage. The vacuum chamber of the present invention includes a plurality of wall members, the plurality of the wall members are connected to each other to construct a chamber main body by connection portions where connection surfaces each of which is part of a surface of each wall member are hermetically connected to each other, and at least part of the connection portions are built-in gap type connection portions each of which has a gap extending along the corresponding connection surfaces inside the connection surfaces and in which peripheries of the connection surfaces are hermetically connected to each other by welding.