A CPU confirms a receivable channel while sequentially changing channel numbers set to an analog front-end unit and specifies an area in which the receivable channel can be received and an area adjacent thereto by referring a receiving channel table by area and an adjacent area table after confirming the receivable channel. After this, the CPU confirms the receivable channel while sequentially setting the channel numbers receivable in the adjacent areas to the front-end unit to specify areas matching with the confirmation result. When the number of specified areas becomes one, the CPU assigns channel numbers to each switch formed of a channel switch group of a user interface unit.