Disclosed is a construction machine that enables an operator to operate a vehicle width changing control lever while visually confirming positions of crawlers. The construction machine includes a lower track structure 1 whose left and right crawler track devices 11A and 11B are adapted to change in spatial interval, and an upper swing structure 2 swingably mounted above the lower track structure. The construction machine further includes a hydraulically actuated cylinder for changing vehicle width, disposed between the left and right crawler track devices, the vehicle width changing cylinder changing the interval between the left and right crawler track devices upon supply and discharge of a hydraulic fluid being controlled by a vehicle width changing control valve, and a vehicle width changing control lever 34 disposed on a left section of a swing body support structure 50 relative to an operator's seat 23, the vehicle width changing control lever operating the vehicle width changing control valve.