Disclosed herein is an absorber with a hole for a metallic magnetic cryogenic detector and an aligning method. More specifically, the present invention is to provide an absorber with a small hole as an aligning mark for a temperature sensor used in a metallic magnetic cryogenic detector. A temperature sensor is bonded on the small hole of the absorber punched by a laser. Using the hole as an aligning mark the temperature sensor can be accurately positioned on the pick-up coil of the measuring means. Thus, the aligning method provides a magnetic measurement with an ideal coupling between the sensor and the pick-up loop. It eventually presents a precise measurement of the energy spectrum absorbed in a metallic magnetic cryogenic detector.