An upper tool device includes: a punch body having a punch blade at a lower end of the punch body; a punch guide into which the punch body is fitted so as to be movable in vertical direction; an adjustment screw member provided above the punch guide, the adjustment screw member screwed with a screw formed on the punch body; a stripper unit including an urging unit urging the punch body in an upward direction; and a retainer collar including a stopper piece having a tip end disengageably engaged with a stopper formed on the punch body. In the device, the stripper unit is detachably provided in the upper tool device, and the retainer collar is provided between the punch guide and the stripper unit in a manner such that the retainer collar can be relatively rotated against the stripper unit.