To provide a tank device which prevents the breakage of a valve body even when a handle is swiftly operated.

A tank device relating to the present invention includes: a tank for storing wash water; a valve body for opening/closing a drain outlet provided in the tank; a connection member which has one end connected to the valve body; an operation part for manually pulling up the other end of the connection member; and a pull-up amount regulation member for limiting the pull-up amount of the valve body by abutting on the valve body. Characteristically, the connection member is partially or wholly made of an extensible spring.