The present invention provides an obstacle detection device that enables stable obstacle detection with less misdetections even when a bright section and a dark section are present in an obstacle and a continuous contour of the obstacle is present across the bright section and the dark section. The obstacle detection device includes a processed image generating unit that generates a processed image for detecting an obstacle from a picked-up image, a small region dividing unit that divides the processed image into plural small regions, an edge threshold setting unit that sets an edge threshold for each of the small regions from pixel values of the plural small regions and the processed image, an edge extracting unit that calculates a gray gradient value of each of the small regions from the plural small regions and the processed image and generates, using the edge threshold for the small region corresponding to the calculated gray gradient value, an edge image and a gradient direction image, and an obstacle recognizing unit that determines presence or absence of an obstacle from the edge image in a matching determination region set in the edge image and the gradient direction image corresponding to the edge image. The small region dividing unit divides the processed image into the plural small regions on the basis of an illumination state on the outside of the own vehicle.