PURPOSE: To enable the connection of a rotary tiller to a machine body in a state sufficiently inclined in machine direction relative to the machine body, by forming a connecting part of a lower link and a rear part of machine body in such a manner that the position of the connecting part of the lower link to the rear part of the machine body is freely adjustable in the longitudinal direction of the machine body.

CONSTITUTION: A bracket 2 is connected and fixed to the right and left of the rear part of a mission case 1 of a tractor and a supporting arm 3 is supported in such a manner as to be freely swingable around a horizontal shaft axis P1 of the bracket 2. Plural bolt holes 2a are opened on the bracket 2 to enable the free selection of the fixing position of the supporting arm 3 with a bolt. A rotary tiller 7 can be connected to a top link 5 and a lower link 4 in a state sufficiently inclined in longitudinal direction relative to the machine body of the tractor.