To conduct working without moving a car body within the reach of an operating device by connecting a slewing mechanism to a mounting bracket rotatably left and right in an attachment for a car, which has a supporting section consisting of the mounting bracket and the slewing mechanism and in which the mounting bracket is installed to the operating device of the construction vehicle vertically rotatably.

The construction vehicle 10 has a lower travelling body 17, a revolving superstructure 18 and an operating device 11. The operating device 11 consists of a boom 19 and an arm 12, and a bucket is mounted at the front end section of the arm 12 in normal excavation works, but the intermediate sections of crushing arms 6 pinching and crushing concrete, etc., are borne rotatably at the front end section of a main frame 5 in normal crushing works, and a hydraulic cylinder 7 for operating the arms is set up between the rear end sections of the crushing arms 6. A crusher 1 has a mounting bracket 3 and a supporting section 2 on the base end side of the main frame 5. Accordingly, operation can be conducted without moving a car body within the reach of the operating device.