An undulation inspection device of the present invention includes: illumination means (line light source 2) that subjects, to illumination, an object to be inspected; light intensity acquisition means (area sensor 3) that acquires light intensity distribution of light that comes, in response to the illumination, from a surface of the object to be inspected; image capturing means (line sensor 4) that obtains only predetermined light out of light that comes from the surface of the object to be inspected; adjustment means (image processing section 20 and light source drive controlling section 21) that adjusts the illumination means (line light source 2), based on the light intensity distribution that is obtained from the light intensity acquisition means; and determination means (defect determination processing means 23) that determines a state of undulation that is formed on the surface of the object to be inspected, based on a result of capturing an image by the image capturing means after adjustment of the illumination means. This makes it possible to provide an undulation inspection device capable of inspecting simply and at a high precision a state of undulation (a difference in film thickness) on a surface of a large substrate (e.g., color filter substrate).