This study aims to investigate the association of financial literacy with individual characteristics (e.g. age and educational attainment) as well as factors which affect gender differences in financial literacy. The data were derived from the “Financial Literacy Survey 2016” which comprised a sample of Japanese men and women aged between 18 and 79. We found that ageing had an inverse U-shaped relationship with financial literacy and an U-shaped one with the degree of over-confidence on financial literacy. Furthermore, female respondents were likely to be less financially literate than male due to being female itself, and differences in the distributions of factors that affect financial literacy (e.g. education and financial assets) and their responses to financial literacy. Not only strategies to assist individual financial decision makings, considering that financial literacy and cognitive functioning decline as people get older, but right education and information sources at the right time are demanded to support the safe asset building of individuals.