An X-ray transmission inspection apparatus includes an X-ray source for irradiating a sample with X-rays, a two-dimensional sensor for detecting transmission X-rays passing through the sample, a sample moving mechanism for moving the sample, a calculation unit for processing an image of the transmission X-rays detected by the two-dimensional sensor, and a display unit for displaying a cross-sectional image. When V1 is a speed at which the sample moves, F is a frame rate of the two-dimensional sensor, A is a sample pitch of the two-dimensional sensor, and LS is a distance between the X-ray source and the two-dimensional sensor, the calculation unit creates a cross-sectional image taken at a distance L from the X-ray source by adding the images of the pixels positioned at an interval of [(LS×V2)/(L×F×A)] in a direction in which the sample moves.