Provided is an injection molding machine (1) including a plasticizing unit (2), an injection unit (3), a communication path (5a) configured to communicate therebetween and having an opening (5b) on the plasticizing unit side which is located on an axis of the screw (21), and a backflow prevention mechanism part (6) configured to close and open the opening on the plasticizing unit side by advancing and retreating the screw (21) in the axial direction, wherein the backflow prevention mechanism part (6) includes a tapered wedge portion (61) having an inclined surface (61a), a driving portion (63) which moves the wedge portion in the forward and backward directions, and a pressing member which is pressed against the inclined surface (61a) by forward movement of the wedge portion and moves the screw toward the opening on the plasticizing unit side.

Provided is an injection molding machine (1) including a plasticizing unit (2), an injection unit (3), a communication path (5a) configured to communicate therebetween and having an opening (5b) on the plasticizing unit side which is located on an axis of the screw (21), and a backflow prevention mechanism part (6) configured to close and open the opening on the plasticizing unit side by advancing and retreating the screw (21) in the axial direction, wherein the backflow prevention mechanism part (6) includes a tapered wedge portion (61) having an inclined surface (61a), a driving portion (63) which moves the wedge portion in the forward and backward directions, and a pressing member which is pressed against the inclined surface (61a) by forward movement of the wedge portion and moves the screw toward the opening on the plasticizing unit side.