Portable phones are getting a trend that s design and thinner configuration becomes more important. Therefore, in order to meet this demand, the entire key top is made of a thin metal, and a thin resin layer is provided on the back surface of the key top and further letter holes are filled with a resin. According to those, the adhesiveness of the key top is improved as well as improvement of hand feeling. In addition, a printed layer for coloring the letters can be provided on the back surface of the key top.