An apparatus for detecting a vehicle path along which a vehicle is traveling. An image of a road presented in front of the vehicle is inputted at intervals of time. The inputted image is processed to detect edge points forming edges in the inputted image and edge gradients at the respective edge points. At least one straight line is assumed. Edge points at which the edge gradients are in a predetermined range determined by the gradient of the assumed straight line are extracted. The extracted edge points are used to calculate an approximate straight line. The approximate straight line has a greatest number of extracted edge points at which the edge gradients are substantially the same. The assumed straight line and the approximate straight line are averaged to provide a new straight line representing one of road sides and/or lane markers.