In recent years, the rapid growth of m-commerce is being driven by various emerging mobile applications and services. Among them, mobile information service is considered to be one of important applications. User’s situation is a key factor in the design of adaptive mobile information services. Personalized and user’s situation dependent information services have been focused as one of value-added services. But little attention has been given to the point on implementing situation dependent information services based on a formal logical approach. In this research, the concepts of our logical architecture, which adopt logical reasoning capabilities of the situation calculus, enable users to receive situation dependent information services. Moreover, because a user’s situation can never exist in isolation from his/her surrounding world, one important purpose of this research is to relate evolution of surrounding circumstances to the architecture, and to model a situation dependent...