A radio LAN (Local Area Network) system includes an access point and a mobile or a fixed station each having a physical layer implemented by a direct spread spectrum system. The LAN system uses different spread codes, maintains transmission power semi-fixed, and selects a frequency and a frequency band in accordance with the kind and amount of information. A data link layer above each physical layer includes an LLC (Logical Link Control) sublayer and an MAC (Media Access Control) sublayer. The MAC sublayer uses a CDMA (Code Division Multiple Access) system as an access system for thereby implementing a data structure in accordance with the kind and amount of information.