While engineering systems that employ new technologies are generally expected to provide convenience, some people remain concerned about the safety of unknown new technologies. How one feels about a new technology is subjective and varies from individual to individual and from situation to situation. Providers of new technologies must consider the impact of potential users’ sense of security about the technology on their behavioral intentions toward it, which can depend on its attributes. Traditionally, however, engineers often do not sufficiently consider social acceptability or potential affective responses by users. The authors have been studying the relationship between people’s affective responses toward new technologies and how such responses affect behavioral intentions. In this chapter, the authors construct technology acceptance models (TAMs) for two different types of technologies, payment service technologies and food technologies, and make a comparative examination of their differences. To summarize the results, the payment service technology TAM did not reflect variables related to a sense of security, while the food technology TAM reflected a sense of security about regulations and risks such as harm caused by food products.