A brake pedal stroke sensor apparatus may include a frame, a hinge shaft fixed to the frame, a pedal arm pivotally coupled to the hinge shaft and rotating with respect to the hinge shaft, an angle sensor that is coaxially aligned to the hinge shaft and fixed to the frame, a sensor lever connected to a rotational shaft of the angle sensor and extending with a predetermined length, and a drive pin formed to the hinge shaft in a predetermined distance from a rotational axis of the hinge shaft and engaged to a distal end portion of the sensor lever so as to transmit change of a rotary angle of the pedal arm to the angle sensor in accordance with a rotation of the pedal arm.