A vehicle door latch device comprising: a body having an accommodating portion that opens on a front surface; a cover plate that is fixed to the body so as to close an opening of the accommodating portion; a back plate that is fixed to a rear surface of the body; a latch, which is pivoted on a latch shaft so as to be rotatable in the accommodating portion, and which is meshable with a striker entering a striker entering groove provided in the body; and a pawl, which is rotatably supported in the accommodating portion, and which is engageable with the latch in a rotating direction, wherein the cover plate comprises: a front-side first shaft hole, through which the latch shaft penetrates; a front-side second shaft hole, into which a first shaft portion is inserted rotatably, the first shaft portion being formed at one end portion of the pawl; a fastening hole, through which a single bolt of a plurality of door fixing bolts penetrates; and a plurality of threaded holes (35, 36), into which other bolts (15B, 15C), other than said single bolt, of the plurality of door fixing bolts are screwed, wherein the latch shaft is formed into a collar-headed shape that is penetratable the front-side first shaft hole and a shaft hole of the latch from a front surface side of the cover plate, wherein the back plate comprises: a rear-side first shaft hole forming portion that forms a rear-side first shaft hole, wherein a distal end portion of the latch shaft which penetrates the shaft hole of the latch is inserted into the rear-side first shaft hole while being prevented from being dislocated therefrom; a rear-side second shaft hole forming portion that forms a rear-side second shaft hole, into which a second shaft portion is inserted rotatably, wherein the second shaft portion is formed at another end portion of the pawl; and a threaded hole forming portion that forms a single threaded hole, into which said single bolt is screwed, wherein threaded hole forming portion is disposed near the rear-side second shaft hole forming portion, and wherein the back plate is shaped so as not to extend to portions corresponding to positions of said other bolts (15B, 15C). a body having an accommodating portion that opens on a front surface; a cover plate that is fixed to the body so as to close an opening of the accommodating portion; a back plate that is fixed to a rear surface of the body; a latch, which is pivoted on a latch shaft so as to be rotatable in the accommodating portion, and which is meshable with a striker entering a striker entering groove provided in the body; and a pawl, which is rotatably supported in the accommodating portion, and which is engageable with the latch in a rotating direction, wherein the cover plate comprises: a front-side first shaft hole, through which the latch shaft penetrates; a front-side second shaft hole, into which a first shaft portion is inserted rotatably, the first shaft portion being formed at one end portion of the pawl; a fastening hole, through which a single bolt of a plurality of door fixing bolts penetrates; and a plurality of threaded holes (35, 36), into which other bolts (15B, 15C), other than said single bolt, of the plurality of door fixing bolts are screwed, a front-side first shaft hole, through which the latch shaft penetrates; a front-side second shaft hole, into which a first shaft portion is inserted rotatably, the first shaft portion being formed at one end portion of the pawl; a fastening hole, through which a single bolt of a plurality of door fixing bolts penetrates; and a plurality of threaded holes (35, 36), into which other bolts (15B, 15C), other than said single bolt, of the plurality of door fixing bolts are screwed, wherein the latch shaft is formed into a collar-headed shape that is penetratable the front-side first shaft hole and a shaft hole of the latch from a front surface side of the cover plate, wherein the back plate comprises: a rear-side first shaft hole forming portion that forms a rear-side first shaft hole, wherein a distal end portion of the latch shaft which penetrates the shaft hole of the latch is inserted into the rear-side first shaft hole while being prevented from being dislocated therefrom; a rear-side second shaft hole forming portion that forms a rear-side second shaft hole, into which a second shaft portion is inserted rotatably, wherein the second shaft portion is formed at another end portion of the pawl; and a threaded hole forming portion that forms a single threaded hole, into which said single bolt is screwed, wherein threaded hole forming portion is disposed near the rear-side second shaft hole forming portion, and a rear-side first shaft hole forming portion that forms a rear-side first shaft hole, wherein a distal end portion of the latch shaft which penetrates the shaft hole of the latch is inserted into the rear-side first shaft hole while being prevented from being dislocated therefrom; a rear-side second shaft hole forming portion that forms a rear-side second shaft hole, into which a second shaft portion is inserted rotatably, wherein the second shaft portion is formed at another end portion of the pawl; and a threaded hole forming portion that forms a single threaded hole, into which said single bolt is screwed, wherein threaded hole forming portion is disposed near the rear-side second shaft hole forming portion, and wherein the back plate is shaped so as not to extend to portions corresponding to positions of said other bolts (15B, 15C).