PURPOSE: To obtain a light, strong and easily manufacturable enclosure by forming a core section % metal boards so that a macine containing space is provided and then bonding a carbon fiber reinforced cement layer to the outer face.

CONSTITUTION: Core section 1A of an enclosure 1 is formed of metal boards 101, 102, 105, 106 so that a machine containing space is provided. A carbon fiber reinforced layer 1B is then bonded to the outer face of the core section 1A. Since sufficiently high strength is provided by the reinforcing layer 1B, thinner metal boards 101-106 can be employed for the cone section 1A, when the same strength in to be provided to the enclosure 1. Consequently, weight of the core section 1A can be reduced and in combination with that the reinforcing layer 1B in lightweight, reduction of the enclosure 1 is enabled. Furthermore, welding of these metal boards 101-106 is facilitated as these boards can be made thin, thus facilitating manufacture of the enclosure 1.