This study examines the substitutability/complementarity between the six legal gambling industries by estimating each industry's sales. It turns out that if the sales of the industries with lower gambling addiction(lottery, sports toto) are to expand, then the sales of highly addictive gambling industries(casino, horse racing, cycle racing, etc.) are significantly reduced. On the other hands, the sales of highly addictive industries tend to increase the sales of other highly addictive gambling industries. Thus, the regulation policy on total sales of gambling industry should be restructured so as to raise the composition of the gambling industries with lower addiction and reduce that of highly addictive industries.