a self - locking type shutter device is provided . the device is arranged in a financial self - service equipment , so as to open or close a cash depositing / withdrawing port of the financial self - help service equipment . the device comprises a frame integrally welded , a gate and a power transmission mechanism . the gate is arranged on the frame by a first rotation shaft and can rotate around the first rotation shaft . the power transmission mechanism is fixed on the frame , so as to provide the gate with rotation power . the power transmission mechanism comprises a motor and at least one unidirectional folding linkage mechanism . the device can be self - locked via the unidirectionally folding linkage mechanism .