A body motion detection device comprising: contrast calculating means for calculating a contrast of a high frequency component and a contrast of a low frequency component of a radiographic image; ratio calculating means for calculating a ratio of the contrast of the high frequency component to the contrast of the low frequency component; and determining means for determining whether or not there is a body motion of a subject contained in the radiographic image based on the ratio, wherein the contrast calculating means is adapted to generate, from the radiographic image, a high frequency image containing the high frequency component and a low frequency image containing the low frequency component, and to calculate the contrast of the high frequency component and the contrast of the low frequency component from the high frequency image and the low frequency image, wherein the contrast calculating means is adapted to calculate the contrast of the high frequency component and the contrast of the low frequency component at at least one analysis point contained in the radiographic image, the at least one analysis point being set for calculation of the contrast of the high frequency component and the contrast of the low frequency component, and wherein the contrast calculating means is adapted to determine, at the at least one analysis point on each of the high frequency image and the low frequency image, a gradient direction of an edge portion contained in an analysis region whose center is the analysis point, and to calculate a contrast along the gradient direction of each of the high frequency image and the low frequency image as the contrast of the high frequency component and the contrast of the low frequency component. contrast calculating means for calculating a contrast of a high frequency component and a contrast of a low frequency component of a radiographic image; ratio calculating means for calculating a ratio of the contrast of the high frequency component to the contrast of the low frequency component; and determining means for determining whether or not there is a body motion of a subject contained in the radiographic image based on the ratio, wherein the contrast calculating means is adapted to generate, from the radiographic image, a high frequency image containing the high frequency component and a low frequency image containing the low frequency component, and to calculate the contrast of the high frequency component and the contrast of the low frequency component from the high frequency image and the low frequency image, wherein the contrast calculating means is adapted to calculate the contrast of the high frequency component and the contrast of the low frequency component at at least one analysis point contained in the radiographic image, the at least one analysis point being set for calculation of the contrast of the high frequency component and the contrast of the low frequency component, and wherein the contrast calculating means is adapted to determine, at the at least one analysis point on each of the high frequency image and the low frequency image, a gradient direction of an edge portion contained in an analysis region whose center is the analysis point, and to calculate a contrast along the gradient direction of each of the high frequency image and the low frequency image as the contrast of the high frequency component and the contrast of the low frequency component.