An automatic immunoassay system comprising: a case provided with a holding plate therein; a cartridge unit disposed inside the case, being coupled to the holding plate and formed with a plurality of wells; a light source unit disposed at one side of the cartridge unit to emit light to the wells; a sensing unit disposed at the other side of the cartridge unit to detect a fluorescence signal generated by light delivered to the wells; a cartridge conveyance unit coupled to the cartridge unit and the holding plate and moving the cartridge unit on the holding plate in a horizontal direction; a tip disposed above the cartridge unit to be sequentially dipped in the plurality of wells; and a tip conveyance unit coupled to an upper surface of the holding plate and moving the tip in an upward/downward direction, characterized in that the system further comprises: a shutter unit disposed between the light source unit and the wells to block light emitted from the light source unit to the wells or allow the light emitted from the light source unit to reach the wells, wherein the shutter unit comprises: a shutter body disposed between the light source unit and the wells to block light emitted from the light source unit from being delivered to the wells; and a shutter pushing portion coupled to an upper portion of the holding plate to move the shutter body. a case provided with a holding plate therein; a cartridge unit disposed inside the case, being coupled to the holding plate and formed with a plurality of wells; a light source unit disposed at one side of the cartridge unit to emit light to the wells; a sensing unit disposed at the other side of the cartridge unit to detect a fluorescence signal generated by light delivered to the wells; a cartridge conveyance unit coupled to the cartridge unit and the holding plate and moving the cartridge unit on the holding plate in a horizontal direction; a tip disposed above the cartridge unit to be sequentially dipped in the plurality of wells; and a tip conveyance unit coupled to an upper surface of the holding plate and moving the tip in an upward/downward direction, characterized in that the system further comprises: a shutter unit disposed between the light source unit and the wells to block light emitted from the light source unit to the wells or allow the light emitted from the light source unit to reach the wells, wherein the shutter unit comprises: a shutter body disposed between the light source unit and the wells to block light emitted from the light source unit from being delivered to the wells; and a shutter pushing portion coupled to an upper portion of the holding plate to move the shutter body. a shutter unit disposed between the light source unit and the wells to block light emitted from the light source unit to the wells or allow the light emitted from the light source unit to reach the wells, wherein the shutter unit comprises: a shutter body disposed between the light source unit and the wells to block light emitted from the light source unit from being delivered to the wells; and a shutter pushing portion coupled to an upper portion of the holding plate to move the shutter body. a shutter body disposed between the light source unit and the wells to block light emitted from the light source unit from being delivered to the wells; and a shutter pushing portion coupled to an upper portion of the holding plate to move the shutter body.