Disclosed is a construction machine capable of securing a turning radius less than the vehicle width, capable of securing a good field of view of an operator seated in the driver's seat, and making possible a decreased the number of components. A mini-shovel is provided with an operating cabin (6) with a door (5) capable of opening and closing an opening surface (16) forming a boarding port (20). The door (5) comprises a single-layer door, and has a flexing portion (5b) which, when the door (5) is in a closed state, is closer to a front pillar (15) than the central portion (21) of said door (5). Said flexing portion (5b) is formed to have: a first area (5b1) formed such that, when the door (5) is in a closed state, said first area (5b1) approaches the opening surface (16) as said first area (5b1) approaches the front pillar (15); and a second area (5b2) which is arranged continuously with said first area (5b1) and nearer the front pillar (15) than the first area (5b1) and which is formed such that said second area (5b2) draws away from the opening surface (16) as said second area (5b2) approaches the forward pillar (15).