PROBLEM TO BE SOLVED: To provide an image distortion detection device and an image distortion detection method capable of highly accurately detecting the distortion of an image of a subject spirally scanned.SOLUTION: An image distortion detection device includes: means for acquiring an image signal of a subject detected by receiving return light from a subject which is spirally scanned and in which a plurality of indices are regularly arranged means for generating an image of the subject by allocating the pixel position in a two-dimensional pixel array in a physical relationship corresponding to the scanning position in a scanning region by scanning light to the acquired image signal in accordance with the detection timing of the image signal and arranging each image signal at the allocated pixel position means for detecting the pixel position of each index in the generated image means for calculating the physical relationship between each of the indices in the image on the basis of the detected pixel position of each index and means for detecting the distortion of each index in the image on the basis of the calculated physical relationship.
