An object detection method which rapidly detects one or more objects existing in an image includes: a primary search step which judges whether an object exists at a predetermined interval by using a simple judgment device requiring a small number of calculation amounts; a range estimation step which estimates a range where an object actually exists from a spatial relationship obtained as a result of the primary search; a secondary search step which performs an object judgment process by using a secondary judgment device capable of performing more detailed judgment than the object judgment device used in the primary search; an object position estimation step which estimates a position where the similarity is maximum in a certain object existing range as an object existing position; and a final search step which judges a final object position.