To provide a press working machine for a folded plate, which can easily perform the folding of the folded plate on a job site, and which brings about the proper finishing of an appearance of a worked portion.

This press working machine for the folded plate includes the base 1, a pair of guides which vertically rise from a surface of the base 1, a slider 3 which ascends/descends along the guide, and a handle which pressurizes the slider 3 in a direction toward the base 1; the guide presents a rod shape in which an external thread is formed; the handle is provided with an internal thread screwed to the guide; the base 1 has a female mold 6 removably provided between the pair of guides; the slider 3 is removably provided with a male mold 7; the center of the female mold 6 is equipped with a pressure streak 9 for pressurizing the bottom surface 8a of the folded plate 8 by an arc-shaped curved surface; a pair of right and left supporting blades 10, the upper edges of which are inclined upward to an outside from an inside are provided in such a manner as to continue into both ends of the pressure streak 9, is provided; and the male mold 7 is equipped with an umbrella-shaped pressure surface 11 for covering the supporting blade 10 and the pressure streak 9 in the lowermost position in which its descent is regulated.