1. A method for superimposing a measured image measured from a semiconductor device and a pattern image showing a pattern of the semiconductor device, the method comprising: acquiring the measured image and a first pattern image showing a pattern of the semiconductor device corresponding to the measured image; acquiring a second pattern image showing a pattern of the semiconductor device; acquiring matching information indicating a correlation of the first pattern image and the second pattern image based on the first pattern image and the second pattern image, wherein the matching information is obtained by adjusting an image size of at least either one of the first pattern image and the second pattern image based on a ratio of a first size of visual field indicating a range on the semiconductor device of the first pattern image to a second size of visual field indicating a range on the semiconductor device of the second pattern image; and superimposing the second pattern image and the measured image based on the matching information to acquire a superimposed image.