Local statutory rape laws in Japan, where the national marriageable age is 16 for females (18 for males), criminalize sexual acts with those generally under 18 unless the offender and the victim are in "serious love toward marriage." The critiques argue that the vagueness of the law interferes "true love" toward legal marriage, rather than protecting minors. This paper provides some evidence on this question by estimating the effects of the passage of statutory rape rule and the changes in the degree of enforcement at local prefectures on teenage marriage. Using the regional data of cohorts born between 1940-1990, we find that the passage of the law significantly encourages new marital formation of women under 18. We do not find evidence that the law increases the divorce rate of women under 18. Therefore, the statutory rape law is likely to prohibit "true love" sexual relationships, encouraging the formal marrital formation as a substitute, without increasing reluctant "cover-up" marriage.