An object detection method includes: acquiring three-dimensional data on an area around a host vehicle by use of a distance measurement sensor; based on map data on an area around a current position of the host vehicle, setting a planned travel area where the host vehicle is going to travel in the future; estimating crossing object existence areas where there currently exist objects which are likely to cross the host vehicle in the future in the set planned travel area; and detecting the object by use of the three dimensional data on insides of the estimated crossing object existence areas.