PURPOSE: To provide a fixing structure for a rigid axle suspension on which local concentrated load does not act by suspending a tandem shaft bn both the ends of a plate spring whose central part is attached to the end of a trunnion shaft, and spreadly providing a buffering member such as rubber on the inside wall face of the box body of a suspension part and its engaging plate, and engaging the end at least one side of the plate spring with the engaging plate.
CONSTITUTION: Axles 14, 14 are suspended at both the ends of plate springs 24A, 24B through a suspension part. A box body formed of right and left side walls 34, 34 and an end wall 36 is firmly attached to both the ends of the axle 14, and an engaging plate 38 is firmly attached to the upper face of the axle 14 on the bottom of the box body, and buffering members 40, 42 such as rubber are spreadly provided on the inside wall face of the box body and the engaging plate 38. An engaging piece 25 formed at the end of the plate spring 24B is engaged with the engaging plate 38, and the piece 25 and the plate 38 are then covered by a cover body 46 through the buffering member 44, and fastened and fixed by a bolt and a nut 48. Thus, there is no necessity for drilling both the ends of the plate spring, and since force acting on the end of the plate spring is dispersed to the engaging plate, the right and left side walls and the end wall, local concentrated load does not act on an axle suspension system, and its service life can therefore be lengthened.