Abstract: A motion sensor for measuring motion information of a subject comprises a coil substrate having transmitting or receiving coils piled one on top of another and a holder in which the coil substrate is mounted. Formed on the holder are curved surfaces to which an adhesive sheet is stuck and at which the holder is attached to a nail of a subject via the adhesive sheet. Further, there is provided a casing where first and second containing space are formed to contain measurement instruments including an adhesive member where a plurality of the adhesive sheets are laid one on top of another, the motion sensor, and the like.