PURPOSE: A press apparatus for manufacturing a reinforcing plate of an oil filter, a reinforcing plate, and an oil filter are provided to prevent screw threads from getting loose by forming recessed surfaces in the corners of a base hole. CONSTITUTION: A press apparatus for manufacturing a reinforcing plate of an oil filter comprises a drawing stage, a piercing stage(4), and a burring stage(8). The drawing stage has a drawing punch(210) and a drawing die(310). The drawing stage forms a container with a bottom part(101) and inclined walls(102a). The bottom part corresponds to a base hole(104) of a reinforcing plate(100). The piercing stage has a piercing punch and a piercing die(320) and pierces the bottom part and parts of the inclined walls of the container. The burring stage has a burring punch(240) and a burring die(340). The burring stage forms flanges(102) and the base hole by expanding and bending the inclined walls of the container.
