PURPOSE: To easily ascend or descend a step difference such as a footpath between rice fields by a method wherein an intermediate wheel is installed between a front wheel and a rear wheel in a light car for agriculture, and the contact surface with the groud of this intermediate wheel is installed at an upper position than the contact surface of the front and rear wheels.

CONSTITUTION: A front wheel 25, a rear wheel 26 and an intermediate wheel 31 are driven by means of a power from an engine 9 through a clutch 11, a transmission 13, differential gears 21, 27, 35. A rubber tyre having a lug is used for the intermediate wheel 31 and the ground contact surface is installed at an upper position than the ground contact surfaces of the front wheel and the rear wheel. With this, in a damp ground such as a farm field, the front wheel 25 and the rear wheel 26 sink into the ground surface and the intermediate wheel having a lug contacts with the ground and a car can travel powerfully and when ascending or descending the path between fields, the intermediate wheel 31 contacts with the edge of the foot path of a rice field and the car can powerfully ride over the edge.