Research Fellow of Japan Society for the Promotion of Science 【Keywords】Human capital; Matching; 【JEL Classification】J24; J31; R23 【Abstract】We estimate the effects of employer tenure on wages based on the instrumental variable method and by using the Japan Household Panel Survey (JHPS/KHPS) from 2004 to 2014. We cannot reject the hypothesis that employer tenure significantly contributes to the wage growth after correcting for the omitted variable biases due to individuals' unobserved abilities and unobserved matching qualities, while the ordinary least squares estimators imply substantial returns to employer tenure. These results are robust across subsamples and do not depend on the estimation method. We conclude that the return to employer tenure may be less important in Japan than has been specified in previous studies.* We are particularly grateful to Katsuya Takii for his appropriate guidance and valuable comments. We would also like to thank Fumio Ohtake, Masaru Sasaki and Nobuyoshi Kikuchi for their useful comments. The data for this analysis, Japan Household Panel Survey (JHPS/KHPS), is