A tank may include: a tank main body having a space and an opening; a lid body covering the opening and a peripheral portion of the opening; a bolt for fixing the tank main body and the lid body in the peripheral portion; a first support portion arranged to surround the opening in a region on a side of the opening with respect to the bolt to support the lid body; a second support portion arranged to surround the opening in a region on the opening side with respect to the first support portion and having a height lower than a height of the first support portion; and a sealing member arranged to surround the opening in the region on the opening side with respect to the first support portion.