A security group management system includes a cellular mobile station (2), two or more devices (3) belonging to a group, and a group management server (1). The group management server comprises a storage unit (11, 13) configured to store information about the cellular mobile station registered by a member of the group and group information about the group in advance; and a group information providing unit (16) configured to supply the group information in response only to an access from the registered cellular mobile station. The cellular mobile station has a group information transmission unit (23) configured to supply the group information to the devices so as to allow the devices to recognize that the devices belong to the group and to perform secure mutual connection and/or resource sharing among the devices.