To provide a tank from which a liquid agent can be led to flow out to the outside through a liquid draining off opening even though the liquid agent has large surface tension, by arranging a liquid draining off member which is formed into a cylindrical shape and projected toward the outward direction of a tank part, and whose end is cut in a direction slant to the center shaft of a cylinder.

A tank 11 is so mounted in a main body 1 that a surface 181 is made to serve as a bottom surface and a valve pushing up pin 201 is arranged to be entered in an opening 182. A ball valve 191 closed by being energized by a spring 192 is opened by being pushed up by the valve pushing up pin 201. Then, a liquid agent in the tank 11 may not be dropped to the outside of the tank 11 by the surface tension of the liquid agent in the case that the end of a liquid draining off member 184 is cut in a direction perpendicular to the center shaft of a cylinder by the restriction of the surface tension of the liquid agent and the opening area of the cylinder, however in the case that the end of the liquid draining off member 184 is cut in a direction slant to the center shaft of the cylinder, balance of surface tension is unbalanced, therefore the liquid agent is led to flow out to the outside of the tank 11 according to gravity.