A lateral dynamic simulation device includes a positioning platform (1), a motor mechanism (2) and a carriage (3). The positioning platform (1) has an upright positioned arm (10). The motor mechanism (2) has multiple degrees of freedom and comprises a base (20), a platform (21) and a plurality of stretchable bars (22) to join the base (20) and the platform (21) by the universal joints (220). The carriage (3) has a space (30) at the frontal portion for carrying passengers and a back portion (31) at the rear portion. The base (20) of the motor mechanism (2) is fixed to the arm (10) of the positioning platform (1) and the platform (21) of the motor mechanism (2) is fixed to the back portion (31) of the carriage (3).