A floor member comprises a lever-pedal mounting part in a front side, an operator's seat mounting part in a rear side, an indoor unit mounting surface part on which an indoor unit is mounted under the operator's seat mounting part, an entrance surface part which is provided in a door side between the indoor unit mounting surface part and the lever-pedal mounting part and on which an operator places a foot at getting-in/off, and a foot rest part which is surrounded by the lever-pedal mounting part, the indoor unit mounting surface part and the entrance surface part. The indoor unit mounting surface part and the entrance surface part form a successive plane successively extending with each other in a position lower by one step than the lever-pedal mounting part and the foot rest part.