An access request message transmission device for a mobile station in a CDMA communication system employing RSMA in which a base station assigns a reverse common channel in response to an access request message from the mobile station, and the mobile station transmits a message to the base station over the assigned reverse common channel. The access request message transmission device includes a hash ID generator for generating a multi-bit hash ID for exclusively using the reverse common channel; a traffic information generator for generating multi-bit traffic information representing traffic information on the reverse common channel; and an access channel transmitter for generating the access request message using the hash ID and the traffic information, and transmitting the generated access request message to the base station over an access channel.