The hair samples of Japanese females during the period from 1881 to 1968 were obtained from various localities of the central area of Japan. Inorganic mercury levels were elevated in unwashed hair samples from prewar periods, especially during 1920s , while elevation of organic mercury levels was conspicuous during 1960s. The increase of inorganic mercury levels in samples from the 1920s is suspected to be due to mercury contamination of hair cosmetics, and increased organic mercury levels in the hair from the 1960s can be explained by active fish consumption.