The invention discloses a hand bag forming machine and a bag body turning device thereof. The bag body turning device comprises an input mechanism, a turning mechanism and an output mechanism, the input mechanism comprises a first roller set, the first roller set comprises a driving shaft and a driven shaft, a plurality of driving wheels and feed rollers are axially and parallelly arranged on the driving shaft, a plurality of driven wheels and paper pressing rollers are axially, parallelly and correspondingly arranged on the driven wheels, the turning mechanism comprises a second roller set, the second roller set comprises a turning roller and a guide wheel mechanism, a lower endless belt surrounds the driving wheels and the turning roller, an upper endless belt surrounds the driven wheels and the guide wheel mechanism, the upper endless belt and the lower endless belt convey a bag body inputted by the input mechanism to the turning roller for turning, and the output mechanism comprises a paper tray and a paper pushing device for pushing the bag body out of the paper tray. By the aid of the turning mechanism, the bag body with an upper opening folded is turned and then outputted to a bottom sticking procedure, so that the hand bag forming machine automatically and continuously runs, and the production efficiency of hand bags is greatly improved.