A pre-filled syringe includes an outer cylinder having a sealed nozzle, and an inner cylinder movable forward and rearward in the outer cylinder and forming a first space between the inner cylinder and an inner front end of the outer cylinder. A first gasket is slidably accommodated in the inner cylinder in a liquid-tight state, a second gasket is accommodated slidably in the inner cylinder in a liquid-tight state and is located rearward from the first gasket to form a second space between the first and second gaskets, and a plunger is attached at a rear end of the second gasket. A third gasket is installed near the front end of the inner cylinder to be slidable in a liquid-tight state between the inner and outer cylinders. A first medicine is stored in the first space and a second medicine is stored in the second space.