The utility model relates to a device for fixing an accelerator and brake pedal actuating mechanism. The device comprises two sets of seat fastening mechanisms, a fixing shaft I, a fixing shaft II anda bandage, the seat fastening mechanism comprises a longitudinal support and a transverse support. One end of the transverse support is connected with the lower end of the longitudinal support. The two sets of seat fastening mechanisms are installed on the two sides of a seat respectively, the fixing shaft II is connected with the transverse supports on the two sides and fixed to the front section of the seat, and the fixing shaft I is connected with the longitudinal supports on the two sides and fixed to the lower portion of a seat headrest. The bandage penetrates through the fixing shaft Ito fix the fixing shaft I below the headrest of the seat, and penetrates through the fixing shaft II to fix the fixing shaft II at the front section of the seat. And the accelerator and brake pedal actuating mechanism is arranged on the fixed shaft II. The fixing device can operate the executing mechanism on the premise that the space of a driver is not occupied, is convenient to install and operate, can be suitable for different seats, has low requirements for bandages, and is stable in performance.