PURPOSE: To recognize a speech rapidly and without fail by a voice input device and to improve the efficiency of a voice input work by inputting the voice while watching the display of the displaying means to show the tempo of the voice input at the suitable time interval.

CONSTITUTION: First, when the electric power source of an interval timer 2 is turned on, the timer 2 generates the pulse at the time interval set beforehand. The pulse is sent through a signal line 5 to a speech recognizing device. A lamp 3 flickers based upon the pulse. Consequently, a talker generates one character by one time of the flickering of the lamp 3, and does not generate during one tome or above of the flickering of the lamp 3 in the clause, the end of sentence, etc. The pulse signal to control the speaking of a talker and the flickering of the lamp 3 is respectively sent through a sound signal line 4 and a signal line 5 to the speech recognizing device. Thus, the sound can be inputted at the constant time interval, and the speech recognizing can be executed rapidly and without fail.