Japan's male smoking rate fell below 30 percent for the first time last year, slipping to 28.8 percent, down 2.3 points from the previous study in 2016, a health ministry survey found.
The national livelihood survey, conducted every three years by the Health, Labor and Welfare Ministry, also found that the female smoking rate fell 0.7 point to 8.8 percent.
By age bracket, smokers in their 20s saw the biggest drops, with the ratio for men falling 4.1 points to 27 percent and the ratio for women dropping 1.9 points to 8.3 percent.
But most smokers are in their 40s, with rates of 37.6 percent for men and 13.4 percent for women.
The male smoking rate has been on the decline since hitting 48.4 percent in 2001.
Growing public awareness of the dangers of smoking is likely behind the downtrend. In April, a law banning smoking indoors in principle at restaurants, offices, hotel lobbies and other public places also took effect.
The survey of people 20 or over counted as smokers those who smoke "everyday" or "sometimes."