PROBLEM TO BE SOLVED: To provide a disposal box disposing of a liquid disposal object easily and safely.SOLUTION: A method disposes of a liquid disposal object 31 by using a water resistant disposal box 10. A water resistant disposal box comprises a box body 11 including an opened upper face and a lid 12 capable of closing an upper face opening 11A of the box body. The box body comprises a paper board including a water resistant film layer formed on both front/rear faces. At least a part of a cutting outer edge of the paper board faces the inside of the box body. The liquid disposal object is put into the box body, the upper face opening of the box body is closed, the liquid disposal object is absorbed slowly by the paper board of the box body from a cutting edge of the paper board, and the liquid disposal object is put into a medical disposal container 40 together with the water resistant disposal box to be closed for disposal.SELECTED DRAWING: Figure 1
