Quantitative application device

The invention belongs to the technical field of medicine application devices, particularly relates to a quantitative application device. The device comprises a medicinal liquid storage bottle, a buffer cavity and an application comb, wherein the medicinal liquid storage bottle is connected to the application comb through the buffer cavity; the buffer cavity is divided into a negative pressure generating cavity and a medicinal liquid measuring cavity by a partition plate, and a three-way conduit is arranged in the negative pressure generating cavity; a first interface of the three-way conduit is in communication with the medicinal liquid measuring cavity, a second interface of the three-way conduit is connected to the bottom of the medicinal liquid storage bottle, and a third interface of the three-way conduit is connected with a negative pressure generating device; and the buffer cavity is made from transparent material, and a scale line is arranged on the side wall of the measuring cavity. The quantitative a