Abstract: A waste liquid receptacle includes first and second cover members for covering first and second openings, respectively. The first cover member is made of a material that is configured to: (i) be plastically deformed upward by a first suction force in a state where a second negative pressure is generated in an upper space; and (ii) plastically deform downward by a depressing force against the first cover member downward in a state where an openable and closable lid is open and the second negative pressure is released. The second cover member is made of a material that is configured: (i) not to be plastically deformed by a second suction force in a state where a first negative pressure is generated in a waste liquid receipt space; and (ii) to be broken without being plastically deformed when a depressing force is applied to the first cover member.

Abstract: A negative pressure is generated in an upper space of a canister due to a suction force of a suction source and, then, a negative pressure is generated in a waste liquid receiving space of a cylindrical body in response to the generation of the negative pressure in the upper space . At this stage of the operation, a first covering member that covers a first opening that opens facing the upper space in a waste liquid treating agent storing portion plastically deforms upward by a suction force caused by a negative pressure in the upper space. On the other hand, when a depressing force that pushes the first covering member downward is applied to the first covering member in a state where an opening and closing lid of the canister is opened so that a negative pressure in the upper space is released, the depressing force is transmitted to a second covering member so that the second covering member is broken.