An aftermarket amplifier of acceleration signal (A) , which is mounted between the potentiometer of the acceleration pedal (B) and the electronic control unit (C) and is programmed to control and to modify the signals from the accelerator pedal. The amplifier improves the acceleration of a car and overcomes to problems occurring during overreacting. The amplifier measures the signals from the acceleration pedal, calculates the change of the angle of the potentiometer of acceleration speed (angular speed) and multiplies the signals from the acceleration pedal by a value which is determined by the angular speed of the potentiometer of the accelerator pedal . Additionally, the amplifier includes a function of a cruise control, which can be controlled with a single control switch (F).