The purpose of this paper is to clarify whether there is a relationship between the labor productivity and the spread of five-day work week system in Japan by applying Data Envelope Analysis (DEA). Thus this paper gives another research field where we can use DEA to analyze the policy evaluation of local authorities. Our main findings are twofold: the five day system is more popular in the region where the economic activity is highly active and in such area the efficiency measured by DEA is also high, which means there is a negative correlation between the labor productivity and the number of annual working days
