To simplify constitution, machining and assembly, to prevent even the formation of a sliding section, by which a film is peeled, to lock one of two shafts or bring it to a free state selectively and surely in response to the opening and closing of a door and to open and close the door smoothly.

The biaxial joint for the car is constituted so that each free end of mounting members to a car body and a door is combined at both ends of a connecting member by hinges. Stoppers 16, 17 are installed to both hinge couplings respectively, one end of a seesaw member 18, in which an intermediate section is supported rotatably to the connecting member, is disposed so as to be able to be selectively engaged at all times, the seesaw member 18 is changed over in response to the rotation of the door and engaged with either of the stoppers 16, 17, and a locking control member 19 is mounted at that time. Stoppers are set up to a car-body side pin and a door-side pin configuring both hinge couplings respectively, one end of the seesaw member 18, in which the intermediate section is supported pivotally to the connecting member, is arranged so as to be able to be selectively engaged at all time, and a control cam member changing over and interlinking the seesaw member 18 to one of the stoppers in response to the revolution of the door is fitted to the car-body side pin.