To provide a navigation technology to a destination without using GPS when getting on a train.

This navigation system is equipped with an acceleration sensor B and a portable information terminal A. The portable information terminal is equipped with storage means for storing station name information and inter-station distance information, an information input means for inputting entraining station name/detraining station name information, an acceleration information input means, a traveling speed calculation means for calculating traveling speed based on acceleration information, a traveling distance calculation means for calculating a traveling distance at the position where the calculated traveling speed reaches zero, a stopover station determination means for determining whether a position in the traveling stop state is pertinent to a stopover station between the entraining station and the detraining station or not based on the calculated traveling distance information and information read out from the storage means, a preceding station determination means for determining whether the station is a preceding station of the detraining station or not when determined that the position is a stopover station, and a preceding station warning means for outputting the effect when determined that the station is the preceding station.