Abstract: A fan unit is disposed on an upper surface of a housing, and includes a fan, a frame member, and a support member. The frame member is disposed to surround an outer circumference of an opening provided in an upper surface of the housing. The support member supports the fan above the opening while being fixed to the frame member. A gap is provided between a lower end of a first surface of the frame member and the upper surface of the housing. A first blocking member is connected to the first surface of the frame member to be slidable in a vertical direction. In a state in which the gap is exposed, at least one second blocking member is inserted through the gap into the frame member to block the opening in the upper surface of the housing.