On a turn frame of an excavation machine, a hydraulic oil tank is placed in the center of a right engine chamber in the front-back direction, a control valve is placed in front of the hydraulic oil tank, a battery is further placed in front of the control valve, and a cool mechanism is placed behind the hydraulic oil tank. The control valve is supported by a support member, and a controller that outputs a signal for driving the control valve is mounted to a side plate part of the support member, thereby to be placed in a position in front of the control valve and above the battery.