To provide a data input device which can be used, by switching, either as a 2-dimension data input device or a 3-dimension data input device.

When a signal selecting part 5 is switched to a 3-dimension data input mode by a switching signal generating part 6, angular speed signals ωa, ωb, and ωc which were outputted from gyro-sensors 2a, 2b, and 2c and then converted to digital signals at A/D conversion parts 4 are converted to rotation amount data θa, θb, and θc by an integration processing part 8, then transmitted to a computer, etc., from a transmission device 10. When the signal selecting part 5 is switched to a 2-dimension data input mode by the switching signal generating part 6, the angular speed signals ωa and ωb are converted to the rotation amount data θa and θb by the integration processing part 8, and a switching signal generating part 9 generates a switching signal based on the angular speed signal ωc, and the rotation amount data θa and θb and the switching signal are transmitted to the computer, etc., from the transmission device 10.