to make it possible to arrange an engine control unit in a narrow arrangement space by , for multiple purposes , using a support member for attaching an operation device . on a machine base supported by a traveling unit , an engine is mounted and a controlling part having an operator &# 39 ; s seat is arranged ; on one of left and right sides of the controlling part , a vehicle accessory is mounted and covered with an accessory cover ; and on a front side of the operator &# 39 ; s seat of the controlling part , and near the accessory cover , a support member is provided upright to provide an operation device . between the accessory cover and the operation device , an engine control unit that controls the engine is arranged , and the engine control unit is attached to the support member .