An electric air gun comprising: a hollow inner barrel guiding a bullet fed into a bullet feed port toward a muzzle; a bullet feed portion having a chamber for housing a bullet, a gas flow path guiding compressed gas supplied from a freely detachable compressed gas cylinder to the bullet feed port in the inner barrel through the chamber of the bullet feed portion positioned in the firing position; a valve placed in the gas flow path and biased in a direction for closing this gas flow path; a firing action mechanism having a movable body that can be freely reciprocated along the inner barrel; a power transmission unit having a motor and transforming the rotational driving force of the motor into the locomotion of the movable body and transmitting the locomotion through a rack and pinion mechanism; and a control unit energizing the motor using a freely detachable battery as an electric power source when detection is performed that a manually operated trigger has been pulled and moving the movable body toward the bullet feed port to actuate the firing action mechanism, characterised in that: the bullet feed portion is installed so that it can be freely reciprocated along the bullet feed port in the inner barrel, and positioned in a firing position for opposing the chamber to the bullet feed port and in a non-firing position for closing the bullet feed port by reciprocating movement; the firing action mechanism is adapted to move the bullet feed portion to the firing position using as power the movement of the movable body toward the bullet feed port and moving the valve to a non-biasing direction at the same time; and the electric air gun further comprises: a hopper with the top thereof open holding a large number of bullets; a hopper striker installed on the movable body and caused to collide with the outer face of the hopper by the movement of the movable body; and a rod installed on the movable body, moved backward together with the movable body, and supplying a bullet in the hopper to the bullet feed portion. a hollow inner barrel guiding a bullet fed into a bullet feed port toward a muzzle; a bullet feed portion having a chamber for housing a bullet, a gas flow path guiding compressed gas supplied from a freely detachable compressed gas cylinder to the bullet feed port in the inner barrel through the chamber of the bullet feed portion positioned in the firing position; a valve placed in the gas flow path and biased in a direction for closing this gas flow path; a firing action mechanism having a movable body that can be freely reciprocated along the inner barrel; a power transmission unit having a motor and transforming the rotational driving force of the motor into the locomotion of the movable body and transmitting the locomotion through a rack and pinion mechanism; and a control unit energizing the motor using a freely detachable battery as an electric power source when detection is performed that a manually operated trigger has been pulled and moving the movable body toward the bullet feed port to actuate the firing action mechanism, the bullet feed portion is installed so that it can be freely reciprocated along the bullet feed port in the inner barrel, and positioned in a firing position for opposing the chamber to the bullet feed port and in a non-firing position for closing the bullet feed port by reciprocating movement; the firing action mechanism is adapted to move the bullet feed portion to the firing position using as power the movement of the movable body toward the bullet feed port and moving the valve to a non-biasing direction at the same time; and the electric air gun further comprises: a hopper with the top thereof open holding a large number of bullets; a hopper striker installed on the movable body and caused to collide with the outer face of the hopper by the movement of the movable body; and a rod installed on the movable body, moved backward together with the movable body, and supplying a bullet in the hopper to the bullet feed portion. a hopper with the top thereof open holding a large number of bullets; a hopper striker installed on the movable body and caused to collide with the outer face of the hopper by the movement of the movable body; and a rod installed on the movable body, moved backward together with the movable body, and supplying a bullet in the hopper to the bullet feed portion.