A communication technique of fusing a fifth generation (5G) communication for supporting higher data transmission rate beyond a fourth generation (4G) system with an Internet of things (IoT) technology and a system thereof is provided. The technique may be applied to an intelligent service (smart home, smart building, smart city, smart car or connected car, health care, digital education, retail business, security and safety related service, or the like) based on the 5G communication technology and the IoT related technology. A method is provided for effectively managing a registration state for a terminal in a 5G core network such as an access and mobility management function (AMF) in a situation of accessing a 5G network via a non-3rd generation partnership project (3GPP) access.