An aspect of the present invention relates to a UE-initiated de-registration method by an AMF in a wireless communication system, and comprises the steps of: receiving, from UE, a de-registration request message that requests de-registration, wherein the de-registration request message includes de-registration type information and first access type information indicating a target access to which the de-registration is to be applied; requesting, when the UE has an established protocol data unit (PDU) session through the target access, an SMF to release the established PDU session; and transmitting a de-registration accept message to the UE depending on the de-registration type.