To provide a connection device for a towing tractor capable of securely preventing the noise caused by springing up of a draw bar pin and coming off of the draw bar pin while traveling.

In a connection device 1 for a towing tractor having a towing bracket 2, a draw bar pin 3, and an operation lever 4, the operation lever 4 and the draw bar pin 3 are mutually connected by a link part 5. One end of the link part is pivotally fixed on an upper end part (bracket 37) of the draw bar pin, and the other end of the link part is connected with a slide part 46 of the operation lever in such a way that a pivotally fixing point (connection pin 54) can slide. An insertion hole 20 in which the slide part 46 is inserted is provided in the towing bracket 2. The connection pin 54 is pressed downward by the operation lever 4 by inserting the slide part 46 into the insertion hole 20 while the draw bar pin 3 is lowered.