A voice guidance system for a vehicle includes a transmitter, a tuner, a touch sensor, a smart ECU, a D-seat speaker, and a P-seat speaker, which are all mounted in a vehicle. It is used for an in-vehicle system, such as a smart entry system, which performs intercommunication with a portable unit. In this guidance system, a smart ECU stores in a memory information indicating that a user has performed predetermined operation with the smart entry system. When it is determined that a user will use the smart entry system, the following processing is performed: voice guidance about the operation procedures for the system is outputted from a driver seat speaker or a passenger seat speaker when information indicating that the user has performed the predetermined operation in the past is not stored in the memory; and voice guidance is disabled when information indicating that the user has performed the predetermined operation is stored.