A sign recognition device includes a sign effective range data recording unit for prestoring effective range conditions shown by a sign and an auxiliary sign, a sign recognition unit for recognizing a sign and an auxiliary sign by using a captured image of a roadway in front of a vehicle, a vehicle information acquiring unit for acquiring vehicle information, a map information acquiring unit for acquiring map information about a map of an area surrounding the vehicle, and a sign effective range determining unit for determining whether or not the vehicle is staying in the effective range specified with the sign and the auxiliary sign which have been recognized by the sign recognition unit by using the effective range conditions stored in the sign effective range data recording unit, the vehicle information, and the map information.