PURPOSE: To provide a mowing cutter unit, capable of preventing a sudden impact to the blade when releasing each stopper of metal fittings of the cutter and of readily setting a torque value required for turning the metal fittings of the cutter.

CONSTITUTION: Metal fittings 17a and 17b of the cutter are each lapped over the blade 16 connected to the lower end part of a crank shaft 8 and each metal fitting is bound to the blade by making a bolt 28 pass through the overlapped part. One of the overlapped surfaces between the blade and each metal fitting of the cutter has plural concave parts 31a to 31c each having the first tapered conical surface 32 around the bolt. The other overlapped surface has plural convex parts 34a to 34c each capable of disengagement and engagement with the concave part and each having the second conical tapered surface 35 capable of surface contact with the first tapered surface. Each metal fitting of the cutter can be prevented from turning by the above-mentioned engagement of each convex part with each concave part.