A processing apparatus has a master processing module and a plurality of slave processing modules. The master processing module has a master recording unit and a slave recording unit recording part of the data recorded in the master recording unit. The slave processing modules access the master processing module when it is necessary to access the data recorded in the master recording unit. When the data to be accessed from one slave processing module is recorded in the slave recording unit, the master processing module transmits the data to be accessed, from the slave recording unit to the one slave processing module. In the processing apparatus such as a base transceiver station communicating with transceivers such as mobile telephones, a reduction in the overall cost of the apparatus and an efficient internal communication are realized, and the overall processing time is reduced.