To provide a forcing hopper apparatus wherein a material can be fed according to a size of only a material hopper without using a cylinder device, which is compact and simple and can be easily treated and carried, and its joint use with another molder can be executed.

A hopper main body 20 wherein a linking part 25 to a feed opening 72 of a heating cylinder 71 is equipped to a lower part of a cylindrical main body 21 having an inner wall surface of the same sectional shape, and an opening and closing cover part 30 capable of being tightly closed is equipped to its upper part; a plunger member 40 which is, in a freely slidable manner, provided along an inner wall surface 22 in the hopper main body 20, and equipped with a vent part 45 capable of being opened and closed; and an air- forcing part 50 which is provided to the opening and closing cover part 30, sends an forced air A into the hopper main body 20 by operation of a forced-air feeder 55 outside the apparatus to advance the plunger main body 40, are provided.