1. A traffic sign determination device comprising: an image capturing device which captures an image of an area in front of a vehicle, the image capturing device being provided on the vehicle; an image recognition section which detects a first traffic regulation sign by performing an image recognition process on the image captured by the image capturing device; a memory which stores map data that includes road link information related to roads constituting a map; a map information acquisition section which, using a current position of the vehicle, acquires a road link including a second traffic regulation sign at the current position of the vehicle, from the map data stored in the memory; a notification device which notifies an occupant of the vehicle of a current final traffic regulation sign based on the first and second traffic regulation signs; and a traffic sign determination section which, when no current first traffic regulation sign is detected on a current road link after turning-right or turning-left of the vehicle, determines the current final traffic regulation sign on the current road link, based on previous first and second traffic regulation signs detected and acquired on a previous road link before turning-right or turning-left of the vehicle, which are also stored in the memory, and based on a current second traffic regulation sign on the current road link.