PURPOSE: To decrease the malfunctions due to misinputs and at the same time to secure the key operating feeling in response to the degree of expertness of an operator, by changing the weighting of the input key according to the accurateness as well an the input speed.
CONSTITUTION: A CPU 241 detects the key input given from an input device 230 according to a key input processing program stored in an input processing memory 243a. Then the CPU 241 counts the key inputs (input speed) and the wrong key inputs per unit time in accordance with the detected key input. Based on these count values, the weighting of a weighting processing table 243b is changed. Thus the weighting of the key input is changed in response to the expertness of an operator, i.e., the input speed and the input accurateness. As a result, the system malfunctions due to misinputs can be decreased and at the same time the key operating feeling is secured in response to the expertness of the operator.