There is provided a technique of reliably preventing actuation of a work machine at engine startup. In a tractor in which a lift valve of a hydraulic system for lifting up/down a work machine is mechanically coupled to a lift lever, conditions for engine startup are set as follows: a reverser lever is at a neutral position； a PTO clutch is disengaged； a seat switch is ON； and the lift lever is at a lowermost position. A switch driving unit is provided on a side face of the lift lever, the side face being orthogonal to a turning direction of the lift lever； a switch is provided so as to be opposed to the switch driving unit when the lift lever is turned to be at the lowermost position； and the lift lever at the lowermost position is detected by the switch.
