Provided is a device capable of suppressing a drop in detection accuracy, and a manufacturing method of a structure. A detection device is a device that irradiates a subject with X-rays and detects the X-rays transmitting through the subject, and includes an X-ray source that emits X-rays, a table that holds the subject, a detector that detects at least a portion of the transmitted X-rays emitted from the X-ray source and transmitted through the subject, and a first guide device and a second guide device that guide movement of the table in a direction parallel to an optical axis of the X-ray source while supporting the table. In this detection device, a guide plane, which is parallel to the optical axis and is a plane to which the movement of the table is regulated, passes through the inside of a detection region of the transmitted X-rays of the detector.