In a Short Message Service (SMS) between private wireless network systems in a multi-zone arrangement, when private wireless network systems, which have been separately placed, are configured in one service area called a multi-zone arrangement, Home Location Register (HLR) information is periodically updated and synchronized through interfacing between the private wireless network systems in the multi-zone arrangement, and making it possible to determine whether or not a receiving terminal is positioned in a service area of which of the private wireless network systems using the synchronized HLR information. An SMS transmission is requested to a call processor of the associated private wireless network system to allow performing SMS message transmission to the associated terminal. That is, it allows an automatic SMS incoming operation at the associated private wireless network system using HLR database information updated periodically, without a separate request for position registration and specific option set by a user.