The present invention relates to a gear ratio variable type steering device which includes a variable gear mechanism between a steering wheel and a gear box for varying a gear ratio based on the speed of a vehicle. The variable gear mechanism includes an input shaft for receiving a rotational force of the steering wheel, an output shaft for transferring a rotational force to the gear box, a variable pulley installed in the outer portions of the input shaft and the output shaft and moved in the axial direction, a belt for connecting the variable pulley, and a motor for varying a gear ratio by moving the variable pulley in the axial direction.