To provide a suspension structure assuring an excellent comfortableness to ride.

The suspension structure is equipped with a front leaf spring 21 whose eye 24 at the forefront is pivoted on a front bracket 25 and the tail is fastened to the oversurface of an axle 22 and a rear leaf spring 23 whose eye 26 at the tail is pivoted on a rear bracket 28 and the forefront is fastened to the undersurface of the axle 22, and further includes an air spring 29 which is interposed between the rear leaf spring 23 and a side rail 3 in such a way as positioned behind the axle 22 and the height H of the air spring 29 is elongated, and thereby the air capacity is increased. This lessens the spring constant of the air spring 29 to a great extent, which allows enhancing the comfortableness of the vehicle.