In order to enable a drain pan to be visually checked for contamination without requiring a complicated operation, the present invention is configured so as to be equipped with: a housing; a drain pan provided inside the housing; a drain pump for pumping up drain water accumulated in the drain pan; an opening provided in a side surface of the housing; and a cover member attached to the opening and covering the opening. When the cover member is detached from the opening at least a portion of the drain pan can be viewed from the opening.