The invention discloses a random-tooth-difference outer cam shock wave roller pin and roller block type differential mechanism and belongs to the technical field of mechanical transmission. The novel automobile differential mechanism is characterized in that a bevel gear is arranged outside an outer-tooth inner retainer, a sleeve structure is arranged inside the outer-tooth inner retainer, and a roller pin and roller block and the outer-tooth inner retainer as well as a left half shaft multi-phase outer cam and a right half shaft inner gear are in pure rolling contact connection and in multi-tooth meshing. Power is input by the bevel gear outside the outer-tooth inner retainer and transmitted to the roller pin and roller block through the sleeve structure of the outer-tooth inner retainer, and then the roller pin and roller block transmits the power to the left half shaft multi-phase outer cam fixedly connected with a left wheel and the right half shaft inner gear fixedly connected with a right wheel so as to enable the left wheel and the right wheel to be differential in speed. A planet gear system in a conventional automobile differential mechanism is omitted, so that the differential mechanism is compact in structure, small in size, supportive of multi-tooth meshing and high in contact ratio, load-bearing capability and transmission efficiency and can be widely used for various wheeled vehicles like automobiles and engineering vehicles needing the differential mechanism.