Abstract: A diecasting apparatus according to the invention comprises an injection cylinder vertically arranged having its upper end communicating with a cavity of dies for diecasting, a melt chamber cylinder coaxially located below the injection cylinder and having an inner diameter substantially the same as that of the injection cylinder, a plunger movable through the melt chamber and injection cylinders to form a melt chamber defined by an upper surface of the plunger and an inner surface of the melt chamber cylinder, thereby to form a hermetically closed space by the melt chamber and cavity, and heating and melting means arranged about the melt chamber cylinder, thereby enabling the molten material to be injected into the cavity through the shortest distance for the shortest period of time, whereby high quality diecast products of high melting point metals are obtained.