PURPOSE: To improve the input operability of a tablet input device by using an available key switch means together with an input pen.

CONSTITUTION: A tablet input device main body 12 containing a tablet board face 11 is provided together with a known input pen 13, and a key switch means (hand key switch) 14 that contains two key switches PF1 and PF2, for example and can be manually operated by an operator. The pen 13 and the switch 14 are connected to the main body 12 via interface cables 15 and 16 respectively. While a tablet input device 10 is connected to a data processor 20 via an input interface cable 17. A CRT monitor 30 is connected to the processor 20. The key input function of the means 14 can be optionally defined and then used together with the pen 13 for improvement of the operator's operability.