<p>A muzzle opening/closing apparatus of an armored vehicle is provided to open and shut the muzzle inside the armored car only because the muzzle outlet cannot be closed in the outside. A muzzle opening/closing apparatus of an armored vehicle comprises a body(11) which is anchored inside the car body and comprises a muzzle(11a); a fastening ring(12) in which a hole(12') in which the body is inserted is formed in the center thereof; a bullet proof plate(13) which is installed outside the body and opens and closes the muzzle of the body; a rotary shaft(14) which enables relative rotation of the bullet proof plate in relation to the body; a spring(17) which is installed in the rotary shaft and pushes the rotary shaft into the car body inside; and a guide body(20) which anchors one end of the spring and guides movement of the rotary shaft.</p>
