PURPOSE: To produce light alloy cranks having high quality for bicycles efficiently by providing plural cavities corresponding to cranks communicating with a charging port via gates on the mating surfaces of a stationary die and a movable die radially and charging molten metal simultaneously thereinto.

CONSTITUTION: Plural cavities 11, 11'W corresponding to cranks communicating with a charing port 9 penetrated longitudinally in the die 5 via gates 12, 12'W are formed on the horizontal mating surfaces 10, 10' of the die 5 fixed on a die plate 7 and a movable die 4 radially around the port 9. The molten metal 14 chared into an injection sleeve 8 suspended and connected to the bottom end of the port 9 is extruded at the same velocity of flow through the gates 12, 12'W into the cavities 11, 11'W by the advancing of a plunger tip 13, whereby plural pieces of cranks are cast simultaneously. By the use of the above-mentioned dies 4, 5, the plural cranks having high quality are produced simultaneously in a short time without producing a large amt. of return scraps.