To make mixed liquid of paint, chemical and the like of a desired compounding ratio without waste by accurately measuring and discharging each liquid from containers storing many kind of liquid respectively, and to easily wash an inside of a discharging opening that is necessary in stirring liquid before discharge and switching over liquid.

This device is provide with a container constructed to store liquid 5 and having a guide out opening 2a of the liquid 5 formed thereon, a cylinder 3 having a suction opening 3a communicating with a discharging opening 3b and the guide out opening 2a formed thereon, and a piston constructed to linearly reciprocate in the cylinder 3 with a designated stroke and to freely rotate around a shaft, and forming a flat surface part 4c on an outer circumference surface 4b from a position which becomes adjacent to the suction opening 3a and the discharging opening 3b when the same is inserted most deeply into the cylinder 3 with the designated stroke, to a tip 4a, so that a gap 13 for liquid 5 to flow between the flat surface part 4c and the cylinder 3 is provided.