Japan has been recognized as having successfully controlled the spread of COVID-19. This study aims to gather insights to combat the spread of infection in our daily lives by observing our purchasing behavior. We use point of sales (POS) data from supermarkets, convenience stores, home centers, drug stores, and electronics retail stores for a nationwide analysis. Our analysis revealed the following. First, the Japanese actively prevented the spread of infection by voluntarily wearing masks, using alcohol-based disinfectants, and gargling. Second, they willingly stayed home during the semi-lockdown. Third, they continued to purchase infection prevention essentials during periods of both low and high levels of infection. We conclude that continuing to wear masks, wash and sanitize hands, and gargle, along with spending more time at home to maintain safe distancing, will be effective in reducing the spread of the virus and combatting the pandemic. Finally, infections and deaths were primarily concentrated in the Tokyo metropolitan area and the Kansai region, where the nature of the spread of the infection was different from that in small and middle-sized prefectures.