A medical injector for animals comprises a fixed body comprising a main housing which is made of a housing piece and another housing piece to form a hollow, a working rod placed in the hollow of the main housing and a restoration spring which is in the main housing to offer the restoration power to the working rod； a pressure unit comprising a pressure part which is inserted slidingly to a rear end of the main housing and is coupled integrally to an end of the working rod； and a handle which is formed integrally to the pressure part； a liquid injection unit comprising a liquid cylinder for forming a medical liquid chamber； and a needle unit which is coupled to a front side of the medical liquid cylinder； and a disinfectant spray unit coupled to the fixed body.
