To provide the mounting structure of a cab, which restrains vibration from being transmitted from a car body frame to the cab without spoiling the function of a torsion bar.

The mounting structure of the cab 2 includes: a rear cab mount 6 capable of being set to a first supporting state where the rear end side of the cap 2 is supported and to a second supporting state; the torsion bar 7 having a fixed end part 72 and a free end part 73; a lever 8 which has an acting part 84 that is extended to the rear part of the vehicle from the free end part 73 and is pressed down by the rear end side of the cab 2, and which is tilted downward according to the pressing; and a part 85 to be locked and a lever locking part 9, which are selectively set to a movement restricted state or a movement allowed state. The acting part 84 of the lever 8 in a state that an upward tilt is allowed transmits torsional reaction force of the torsion bar 7 to the cab 2 so as to push up the rear end side of the cab 2 from below, so that the upward tilt of the lever 8 is restricted and the rear end side of the cab 2 is separated from the acting part 84 in such a state that the rear cab mount 6 is set to the first supporting state.