To switch a back light so as to facilitate the viewing of a display of a monitor panel device even in work performed by lighting a working light during the daytime.

This construction machine includes: a relay switch 29 for switching on/off the working light 32; a switching switch for switching a daytime mode and a night mode for the brightness of a back light; and a working light switch 14 which controls operations of the respective switches. The working light switch 14 is so constructed as to perform switching among a first position in which the relay switch 29 is set at a light-off position and the switching switch of the back light is set at the daytime mode position, a second position in which the relay switch 29 is set at an illumination position and the switching switch of the back light is set at the night mode position, and a third position in which the relay switch 29 is set at the illumination position and the switching switch of the back light is set at the daytime mode position.