A front case at a display section side 1 of frame shape is formed of a metal material having strength and a bus-tab-shaped draw frame 4 formed by drawing metal plate is fixed at the external side of the front case at the display section side 1 by heat adhesive 10 to be integral with the front case at the display section side 1. Two L-shaped frames 5 formed by bending metal plate materials are fixed at the internal side of the front case at the display section side 1 by two heat adhesives 11 to be integral with the front case at the display section side 1. The front case at the display section side 1, the two L-shaped frames 5, and the bus-tab-shaped draw frame 4 are integral with each other to have sandwich structure.