This paper statistically investigates the charging system of Japanese domestic air fares and predicts the effect of the revision of the current system on the consumer`s surplus. Using 222 observations of cross-sectional data from 1995, this paper empirically demonstrates that (a) the fares in the long haul markets were set higher regardless of the number of passengers. (b) in the outstandingly dense markets, the fares were set higher than the predicted full cost level, and (c) in the thin and shorter haul markets, fares were a little lower. Considering the price elasticity of these three types of routes, this paper concludes that the reduction of air fares in the long haul markets (especially dense markets) to the "distance-proportional level" would lead to a substantial gain in consumer`s surplus. Furthermore, this gain would surpass the loss of consumer`s surplus that might arise in shorter haul routes. There still remains substantial room for the Japanese government to improve the consumer`s benefit without worsening, and possibly even improving, the status quo of the airlines.