Abstract: A pair of side frames, each comprising a side plate and a connecting arm, are provided on the opposite sides of a tractor body and connected together at their front ends by a connecting member. Each of the side frames has front and rear mount portions for a front loader and is removably provided at its front end with an upright frame extending upward in front of the bonnet of the tractor. The upright frame includes a mount member at the base portion thereof and an upright member removably attached to the mount member. The upper ends of the upright members are interconnected by a connector having a turnable rod extending therethrough and provided with a lift arm at each end. A front three-point linkage for attaching a front working implement to the tractor is mounted on the side frames and the upright frames. A lift cylinder is provided between the lift arm and a lower portion of each of the upright frames.