PURPOSE: To make a whole construction simple and small in size by connecting a die-housing body for housing an upper die and a die-housing body for housing a lower die to each other into a common loop and carrying in and out the upper and lower dies by a single set of die carrying in/out device.

CONSTITUTION: For carrying in a lower die 9D and an upper die 11D to respective die-housing bodies 83 of a die changing device from a bending machine; the slider 143 of a die carrying in/out device 85 is advanced to the side of the bending machine, and upper and lower ratch-levers 151U, L are locked with upper and lower holders 35, 19 respectively. Next, the holders 35, 19 are housed in respective die-housing bodies 83, when the slider 143 is retreated. In this way, the upper and lower dies 11D, 9D held by the upper and lower holders 35, 19 are carried into respective die-housing bodies 83. Further, the dies 11D, 9D in respective bodies 83 are carried out by performing inversely said operation.