An operator cab 53, which is mounted rotatable on the vehicle body 51 of a hydraulic mini-shovel 50, comprises a cab box 1, a door 2, upper and lower link members 3 and 4, a slide member 6, a closed door lock 7, an opened door lock 9 and a handle 13. The cab box 1 has an internal cab room 1a and an entrance 15, which leads into the cab room 1a. The door 2 closes and opens the entrance 15 when it is moved forward and rearward, respectively. The upper and lower link members 3 and 4 have fixed ends 3a and 4a, each of which is connected pivotally to the cab box 1, and moving ends 3b and 4b, each of which is connected pivotally to the front end of the door 2. The slide member 6 is connected pivotally to the rear end of the door 2 so as to swing freely and slides along a slide rail 5, which is provided externally on the cab box 1. The closed door lock 7, which is provided at the front end of the door 2, engages with a closed door striker 8, which is provided on the cab box 1, when the door 2 is closed. The opened door lock 9, which is provided at the front end of the door 2, engages with an opened door striker 10, which is provided on the cab box 1, when the door 2 is opened. The handle 13 is provided at the front end of the door 2 and interlocked with the closed door lock 7 and the opened door lock 9.