The invention discloses a steering column crumpling energy absorbing device and a steering column assembly, and relates to the technical field of automobile anti-collision protection. The steering column crumpling energy absorbing device and the steering column assembly are invented in order to simplify the structure and improve the guiding performance and the stability in the crumpling energy absorbing process. The steering column crumpling energy absorbing device comprises a fixed support fixedly connected with an automobile body and a sliding support fixedly connected with a steering column of an automobile, a sliding groove with the two ends closed are formed in the sliding support in the axial direction of the steering column, a crumpling piece which can slide in the sliding groove is arranged in the sliding groove in a matched mode, the fixed support is connected with the sliding support through the crumpling piece, the sliding groove comprises a first section and a second section which are mutually communicated, the first section is narrower than the second section and the crumpling piece is arranged in the second section in a matched mode. The steering column crumpling energy absorbing device is used for an automobile steering system.