To solve a problem of a conventional technology that a strap cannot have easily been fitted to a mobile apparatus.

Opening are formed respectively at the first side of a case of a mobile phone 4, and a second side tangent to the first side, and a straight line hole 3 perspective from the first side to the second side is formed. A user of the mobile phone 4 threads an annular string provided to one end of the strap 5 through the hole 3 formed at the case of the mobile phone 4 from the opening of the first side 1 or the opening of the second side 2 and threads the other end of the strap 5 to the ring of the annular thread to fix the strap 5 to the mobile phone 4. The inner wall of the hole 3 may be curved.