To enhance working efficiency in attaching and detaching a heat exchanger to and from a frame.

In this construction machine, a bottom plate 5A1 of a turning frame 5 is provided with an elongate hole 21 allowing the heat exchanger 15 to vertically pass through, and the heat exchanger 15 is attached and detached to and from the turning frame 5 through the elongate hole 21. Consequently, even when the front side of the heat exchanger 15 is stored in a recessed part 14F provided at a rear face part 14B of a cab 14, there is no need to detach the cab 14, a counterweight 6, and the like beforehand from the turning frame 5 to secure a working space for performing attaching/detaching work of the heat exchanger 15. As a result, working efficiency in attaching and detaching the heat exchanger can be enhanced.