A portable telephone (1) comprises a first structure (2) including a display portion (2a) such as a liquid crystal screen and a second structure (3) including an operation portion (3a). A projection (4) to engage with a guide groove (5) formed in the side surface of the first structure (2) is formed on the side surface of the second structure (3). Thus, by sliding the second structure (3) to one end side of guide groove (5), pivoting the second structure (3) at the end to the rear surface of the first structure (2), and sliding the second structure (3) to the other end side of the guide groove (5), the second structure (3) is set, from a closed state in which the major surface of the first structure (2) opposes the major surface of the second structure (3), to an open state in which the display portion (2a) and operation portion (3a) are exposed to the outside. In this manner, in the closed state, the second structure (3) covers the display portion (2a) of the first structure (2). This prevents the display portion 2a from causing inconveniences, thereby enhancing the durability.