To improve, for example, the property of incorporation into a tub by facilitating repair and the like.

A drain plug device 10 comprises: a drainage mechanism body 5 supporting a plug 12 on a drain inlet member 11, which is fixed to a bottom surface of the tub, via a hoisting and lowering unit 30; an operation mechanism body 6 for supporting an operation button 14 on a button case 40, which is fixed on the upside of the tub, via a switch unit 60; and a wire 8 which is arranged in a pipe interposed between the mechanisms 5 and 6 so as to connect the units 30 and 60 together. The mechanism body 6 is equipped with a plug case 45 which is connected to a corresponding end of the pipe 7, a button case 40 which forms a lower opening 44 so as to be coupled to the plug case 45, and a holder 50 which is partially arranged on the side of the case 45 from the opening 44 when inserted into the button case by supporting the unit 60. The holder 50 has a mounting part 56 which is formed in such a manner that the holder 50 can be wholly inserted into the case 45 from the opening 44 of the button case, and which is provided on an upper outer periphery so as to be engaged with and fixed to the button case by turning at a prescribed angle in the state of being partially inserted into the opening of the button case.