The utility model provides a sheet metal's stretching device, it includes bedplate and stand, surperficial two of bedplate sets up a set of stand respectively, two one side tops that the stand is corresponding do not set up one and hang the post, one side top that two other stands correspond do not be by dig a circular openning outward toward the lining, wherein, the opposite side department placed in the middle of a stand is the level form and sets up a layer board, the layer board is the slope form by the strut and props up, the axostylus axostyle that rolls section of thick bamboo one end outside imbeds in the circular openning that corresponds department stand one side upper portion, the axostylus axostyle end that rolls another outside of a section of thick bamboo is passed outside toward behind the circular openning on upper portion on one side of another stand by the lining, and extend one section, and this the first axostylus axostyle end that extends away sets up a fluted disc, the pivot end of motor one end sets up a fluted disc, the terminal fluted disc of pivot in the motor imbeds the linking with the fluted disc that rolls section of thick bamboo one end outside each other.