A parking space is detected by using a range sensor. Distance data in a predetermined period is collected by using the range sensor according to a user's selection and mapping the collected distance data on a coordinates system based on a parking space searching vehicle. The collected distance data are classified into short distance data and long distance data. Parking-available distance data, is calculated. Whether the parking space exists based on the calculated parking-available distance data is checked. The parking space searching vehicle is stopped by controlling an active braking apparatus or recommending a driver to stop the parking space searching vehicle by means of a voice and alarm sounds when it has been checked that the parking space exists.