An injection machine which includes a mold falling prevention device that prevents a mold fixed to a mold fixing surface from falling off from the mold fixing surface and in which are provided a bottom edge restriction member at a lower portion of said mold fixing surface so that its vertical position is variable, for implementing restriction so that the bottom edge portion of the mold does not separate from the mold fixing surface, first and second intermediate restriction members at intermediate level portions of the mold fixing surface so that their horizontal positions are variable, for respectively implementing restrictions so that a one edge portion of the mold and an other edge portion thereof in the horizontal direction do not separate from the mold fixing surface, and a vertical direction position determination mechanism that receives and stops a bottom edge surface of the mold and determines a position of the mold in the vertical direction.