PROBLEM TO BE SOLVED: To restrain an occurrence of trouble giving a driver an oppressive feeling, resulting from inward deformation of a side wall of a driver's cabin with respect to a car frame by an external force, at falling-down on colliding, while attaining reduction in weight and cost. SOLUTION: In a driving space holding structure of a working vehicle equipped with the driver's cabin 2 in a traveling machine body 1, a wire 29 is laid for deforming, by means of external force F from the side of the driver's cabin 2, side walls 13, 23, 24 which receive the external force F across the traveling machine body 1 and an upper and lower intermediate part of right and left side walls 23 of the driver's cabin 2, so as to evaginate the upper and lower intermediate part outwardly.
