A package inspection system includes a conveyor mechanism 6, an X-ray generator 10 applying X rays to a package W1 conveyed by the conveyor mechanism 6, an X-ray sensor 13, and an optical sensor 15. First image data showing the outline of the content of the package W1 are generated based on detection output from the X-ray sensor 13. Second image data showing the outline of the wrapping of the package W1 are generated based on detection output from an optical sensor 15. The relative position of the wrapping and the content is determined based on the first and second image data, so that failures, e.g., the content caught in a seal of the wrapping can be detected accurately. The package inspection system can accurately determine a position of a wrapping and the content of a package even if a package has a light non-transmissive wrapping.