An injection apparatus that injects molding material into a mold through an injection cylinder operated by fluid pressure of an incompressible fluid to fill the mold with the molding material, the apparatus comprising: a pressure accumulating portion, which is connected to an operation chamber in the injection cylinder to accumulate the fluid pressure; a speed reduction mechanism for reducing the speed of the injection cylinder; and a passage for selectively supplying and draining the incompressible fluid to and from the injection cylinder, wherein the injection cylinder includes a movable rod (17a, 17d), a plunger is connected to the rod (17a, 17d), the injection apparatus being characterized in that the speed reduction mechanism is located on the outside of the injection cylinder and the plunger, the speed reduction mechanism includes an actuating member (41; 50) moving integrally with the rod (17a, 17d) of the injection cylinder, a restriction member (44; 52) mounted in the passage, the restriction member (44; 52) being movable in conjunction with movement of the actuating member (41; 50), the restriction member (44; 52) variably restricting the passage, and a receiving member (42; 51) for movably receiving the restriction member (44; 52), the receiving member (42; 51) includes a supply port (42b; 51a) connected to the passage and a drain port (42c; 51b) communicating with the supply port (42b; 51a), and the restriction member (44; 52) has a restriction (44b; 52a) formed to restrict the passage to decrease the flow rate of the incompressible fluid from the supply port (42b; 51a) to the drain port (42c; 51b). a pressure accumulating portion, which is connected to an operation chamber in the injection cylinder to accumulate the fluid pressure; a speed reduction mechanism for reducing the speed of the injection cylinder; and a passage for selectively supplying and draining the incompressible fluid to and from the injection cylinder, wherein the injection cylinder includes a movable rod (17a, 17d), a plunger is connected to the rod (17a, 17d), the injection apparatus being characterized in that the speed reduction mechanism is located on the outside of the injection cylinder and the plunger, the speed reduction mechanism includes an actuating member (41; 50) moving integrally with the rod (17a, 17d) of the injection cylinder, a restriction member (44; 52) mounted in the passage, the restriction member (44; 52) being movable in conjunction with movement of the actuating member (41; 50), the restriction member (44; 52) variably restricting the passage, and a receiving member (42; 51) for movably receiving the restriction member (44; 52), the receiving member (42; 51) includes a supply port (42b; 51a) connected to the passage and a drain port (42c; 51b) communicating with the supply port (42b; 51a), and the restriction member (44; 52) has a restriction (44b; 52a) formed to restrict the passage to decrease the flow rate of the incompressible fluid from the supply port (42b; 51a) to the drain port (42c; 51b). an actuating member (41; 50) moving integrally with the rod (17a, 17d) of the injection cylinder, a restriction member (44; 52) mounted in the passage, the restriction member (44; 52) being movable in conjunction with movement of the actuating member (41; 50), the restriction member (44; 52) variably restricting the passage, and a receiving member (42; 51) for movably receiving the restriction member (44; 52), the receiving member (42; 51) includes a supply port (42b; 51a) connected to the passage and a drain port (42c; 51b) communicating with the supply port (42b; 51a), and the restriction member (44; 52) has a restriction (44b; 52a) formed to restrict the passage to decrease the flow rate of the incompressible fluid from the supply port (42b; 51a) to the drain port (42c; 51b).