PURPOSE: To provide a torsion bar device which can set the spring constant of the front mount of a vehicle small and improve drive feeling.

CONSTITUTION: The arm parts 12a, 12b, 13a, and 13b of two torsion bars 10a and 10b arranged in parallel to a tilt shaft 5 are installed in turnable manner on the brackets 7a, 7b, 9a, and 9b through a pin 17, and the members 8a and 8b on a cab side and chassis frames 2a and 2b are connected in sleeve-tuckled-up form, and both the torsion bars 10a and 10b are connected so that a constant distance is kept by the connecting members 16a, 16b, and 16c. Then, the partial charged load of a front mount can be lightened by arranging the brackets 7a, 7b, 9a and 9b in the vicinity of the position of the center of gravity in the longitudinal direction of the car of the cab at a normal position.