To provide a cellular phone which reduces user's burden for open and close operations of the cellular phone, prevents damage of the device body caused by the open and close operations, and effectively realizes a support function for device open and close operations without decreasing design flexibility.

An angle sensor 11 detects angle changes of a rotation connector 3, and a measurement and calculation part 13 calculates an angle and an angular velocity based on the detection result of the angle sensor 11 to determine whether to open or close the cellular phone. Based on the determination result, the measurement and calculation part 13 allows a coil controller 14 to apply a voltage so as to generate a magnetic field in the direction that coils 15 and 16 repel or attract each other. The coil controller 14 excites a magnetic field by applying a voltage according to the instruction from the measurement and calculation part 13. In addition, a rotation dumper 12 absorbs shock caused by open and close operations to obtain smooth open and close operations.