An information device for use with an engine of a vehicle includes a lighting device for providing information about a power position of the vehicle, an engine running detection device for detecting engine running, a gear shift position detection device for detecting gear shift position, and an illuminance control device for controlling illuminance of the lighting device. When a detection is made by the engine running detection device that the engine is running and by the gear shift position detection device that the gear shift position is other than in a P or N range, the illuminance control device reduces the illuminance of the lighting device compared with the illuminance of the lighting device when the gear shift position is in the P or N range.