The aim of this study was to develop a self-administered scale based on features of Internet addiction and the smartphone’s characteristics, and to identify smartphone addicts. We hypothesized smartphone addiction has many aspects that are similarthose of Internet addiction and substance addiction, suchtolerance, withdrawal, compulsive behavior, and daily-life function disturbance. The Smartphone Addiction Inventory (SPAI)specifically designed on the basis of the Chen Internet Addiction Scale (CIAS) with its well-organized five-factor structure. This study examined the reliability and verified the construct validitythe new-established Smartphone Addiction Inventory.