A continuous screw tightening machine with washer stacking supply mechanism comprising: a tightening machine body on which a driving machine is mounted, connecting a bit for screw tightening rotated/driven by the driving machine detachably and rotatably and arranged capable of advancing/retreating between a standby position and a tightening possible position by the bit, a tip-end block provided below the tightening machine body, provided with a washer temporary accommodating portion for accommodating one washer capable of being withdrawn downward, and arranged on a tightening target spot, a screw-and-washer supply mechanism body arranged between the tightening machine body and the tip-end block, having an accommodating region for stacking a large number of the washers in stacked arrangement on a rear side and capable of concentric arrangement of screws between the bit and the washer, a washer sequential supply mechanism incorporated in the accommodating region of the screw-and-washer supply mechanism body from a side portion to a lower part and provided with a washer feeding body for engaging a concave portion corresponding to an outer shape of the washer with an outer periphery of the washer and feeding it to the washer temporary accommodating portion, a screw rope magazine accommodating a screw rope to which a large number of the screws are connected at a constant interval by a band-shaped member, capable of being fed out and detachably arranged on a rear part side of the screw-and-washer supply mechanism body, and a screw sequential supply mechanism incorporated in the screw-and-washer supply mechanism body, characterized in that during the retreating of the tightening machine body back towards the standby position, the washer is automatically supplied to the washer temporary accommodating portion by the washer sequential supply mechanism, and one of the screws connected to the screw rope from the screw rope magazine is automatically supplied by the screw sequential supply mechanism so as to be concentrically arranged between the washer and the bit, and during advancing of the tightening machine body away from the standby position, the washer sequential supply mechanism is automatically set to a feeding preparation attitude for the subsequent washer, and the screw sequential supply mechanism is automatically set to a feeding preparation attitude for the subsequent screw. a tightening machine body on which a driving machine is mounted, connecting a bit for screw tightening rotated/driven by the driving machine detachably and rotatably and arranged capable of advancing/retreating between a standby position and a tightening possible position by the bit, a tip-end block provided below the tightening machine body, provided with a washer temporary accommodating portion for accommodating one washer capable of being withdrawn downward, and arranged on a tightening target spot, a screw-and-washer supply mechanism body arranged between the tightening machine body and the tip-end block, having an accommodating region for stacking a large number of the washers in stacked arrangement on a rear side and capable of concentric arrangement of screws between the bit and the washer, a washer sequential supply mechanism incorporated in the accommodating region of the screw-and-washer supply mechanism body from a side portion to a lower part and provided with a washer feeding body for engaging a concave portion corresponding to an outer shape of the washer with an outer periphery of the washer and feeding it to the washer temporary accommodating portion, a screw rope magazine accommodating a screw rope to which a large number of the screws are connected at a constant interval by a band-shaped member, capable of being fed out and detachably arranged on a rear part side of the screw-and-washer supply mechanism body, and a screw sequential supply mechanism incorporated in the screw-and-washer supply mechanism body, characterized in that during the retreating of the tightening machine body back towards the standby position, the washer is automatically supplied to the washer temporary accommodating portion by the washer sequential supply mechanism, and one of the screws connected to the screw rope from the screw rope magazine is automatically supplied by the screw sequential supply mechanism so as to be concentrically arranged between the washer and the bit, and during advancing of the tightening machine body away from the standby position, the washer sequential supply mechanism is automatically set to a feeding preparation attitude for the subsequent washer, and the screw sequential supply mechanism is automatically set to a feeding preparation attitude for the subsequent screw.