The needs for accessibility of cellular phones to Web based client-server systems are increasing. For this ac- cess, efficient management of the context data must be im- plemented on the cellular phone. However, physical restric- tions of the cellular phone make it difficult to manage con- text data by applying the conventional methods. Addition- ally, the conventional methods do not show sufficient perfor- mance to tolerate heavy accesses from cellular phones. We therefore design a new session management mecha- nism that enables cellular phone to use Web client-server system efficiently. To do so, we decide to utilize key concepts in the CDS mechanism, which was previously developed by us in order to implement session management on the Web. By utilizing the CDS mechanism, we develop a new session management mechanism that connects cellular phone and Web systems. Then, we can actually implement the session management with high safety and reliability. The result of a benchmark evaluation shows that proposed mechanism has higher performance than the conventional mechanism.