To solve the problem that it is difficult for a user to catch a voice guide when the voice guides are output as "words" from a plurality of devices, in the devices each of which computes masking information from dark noise nearby equipment, selects a frequency and sound pressure on the basis of it, and generates and outputs the guide tone of the frequency.

Whether state information on other equipment is received by a communication means 11a is monitored and when the state information is received, a control means 13a compares importance data showing the importance of a voice guide in the state information on the other equipment received by the communication means 11a with importance data showing the voice guide of the own equipment, read out of an importance data storage means 12a. When a comparison result showing that the value of the importance data of the other equipment is larger is obtained, the control means 13a transmits the importance data of the own equipment and information on an equipment state of the own equipment to the other equipment by using the communication means 11a, performs fade-out processing for interrupting the voice guide, and makes the voice guide a standby state.