The injection apparatus 100 is provided that can allow repair or replacement of an actuator 130 while maintaining a drip-proof state, and that can further maintain the drip-proof state without a cover. The injection apparatus 100 includes a syringe holder 110 on which a syringe filled with a liquid medicine is mounted, a presser 115 that pushes out the liquid medicine from the mounted syringe, an actuator 130 that moves the presser 115 forward or backward, the actuator 130 including a feed screw nut 134, a feed screw shaft 133, a motor 132, and a transmission mechanism 180 that transmits rotation from the motor 132 to the feed screw shaft 133, wherein the feed screw nut 134, the feed screw shaft 133, the motor 132, and the transmission mechanism 180 are housed in a case 170 of the actuator 130.
