PURPOSE: To improve operability by controlling an operating system by a voice control decoder and performing conversion to control signals for directly generating a desired action.

CONSTITUTION: A voice recognition software 120 is operated under a Macintosh operating system 132 and is controlled by a command 123 from a voice control driver 128. Then, voice macro stored beforehand and generated voice are compared and the voice is recognized by matching. Also, the voice control decoder 130 writes an event to the event queue of the operating system 132, controls the operating system 132 and performs the conversion to the control signals for directly generating the desired action to be supported. Then, the need of converting the uttered voice to the control signals expressed by a prescribed format specified by a keyboard is eliminated and the operability is improved.