To provide an automatic manner mode changeover system where a manner mode is automatically switched during movement at a high-speed so as to allow a user to save time and labor for the mode switching thereby eliminating the need for the user to execute a switching operation to the manner mode.

When a control section 3 discriminates that an on-vehicle adaptor is connected to a connection port 6 and discriminates high-speed movement for a prescribed time depending on information from a wireless section 2, or when a user operates an operation section 4 to connect the on-vehicle adaptor to the connection port 6 and automatically sets the manner mode, and when the control section 3 discriminates high-speed movement for the prescribed time or over depending on information from the wireless section 2, the automatic manner mod changeover system respectively selects the manner mode where the system informs the user about the arrival of an incoming call without ringing. The system automatically releases the manner mode when the high-speed movement changes into low-speed movement.