An injection molding machine, comprising: a cylinder that feeds a molding material; a screw that is rotatably and advanceably/retractably provided in the cylinder; a plasticizing motor that rotates the screw; and a rotation transmission part that is provided in a rear side of the screw in an axial direction of the screw and configured to transmit rotation of the plasticizing motor to the screw; wherein the rotation transmission part includes first and second transmission members (23, 24) provided in a passage where the rotation of the plasticizing motor is transmitted to the screw, the first transmission member being provided toward the plasticizing motor, and the second transmission member being provided toward the screw, wherein the first and second transmission members (23, 24) are connected to move relative to each other, the injection molding machine further comprising: a base; a movable member that advances/retracts 35 together with the second transmission member with respect to the base; a fixing member fixed to the base and including an insertion hole through which the first transmission member is inserted; and an injection motor that moves the movable member with respect to the base and moves the screw inside the cylinder, wherein the injection motor is fixed to the movable member, wherein the injection motor is configured to advance/retract together with the movable member, characterized in that the injection motor is inserted into a recess part formed in the fixing member when the movable member is retracted. a cylinder that feeds a molding material; a screw that is rotatably and advanceably/retractably provided in the cylinder; a plasticizing motor that rotates the screw; and a rotation transmission part that is provided in a rear side of the screw in an axial direction of the screw and configured to transmit rotation of the plasticizing motor to the screw; wherein the rotation transmission part includes first and second transmission members (23, 24) provided in a passage where the rotation of the plasticizing motor is transmitted to the screw, the first transmission member being provided toward the plasticizing motor, and the second transmission member being provided toward the screw, wherein the first and second transmission members (23, 24) are connected to move relative to each other, the injection molding machine further comprising: a base; a movable member that advances/retracts 35 together with the second transmission member with respect to the base; a fixing member fixed to the base and including an insertion hole through which the first transmission member is inserted; and a base; a movable member that advances/retracts 35 together with the second transmission member with respect to the base; a fixing member fixed to the base and including an insertion hole through which the first transmission member is inserted; and an injection motor that moves the movable member with respect to the base and moves the screw inside the cylinder, wherein the injection motor is fixed to the movable member, wherein the injection motor is configured to advance/retract together with the movable member, characterized in that the injection motor is inserted into a recess part formed in the fixing member when the movable member is retracted.