This paper examines opening hours, store quality, and price decisions by retailers. We consider a scenario in which the investment in store quality is more costly for longer opening hours. This scenario is suitable for a case where a retailer invests in the brand proliferation in order to attract consumers. This is because longer opening hours cause additional wages and administrative costs in order to handle the brand proliferation. We show that a retailer with shorter opening hours chooses higher brand proliferation and charges lower prices. We also examine the impact of deregulated opening hours on social welfare. We find that the liberalization on opening hours is desirable in view of social welfare.