A digital broadcast receiving device includes a multi-channel tuning device, a first de-multiplexing device, a second de-multiplexing device. The multi-channel tuning device includes a plurality of locking devices, wherein the locking devices are arranged to lock a broadcast signal at a plurality of frequency points, and respectively output a plurality of data streams that correspond to the frequency points. The first de-multiplexing device includes a plurality of first de-multiplexing units, wherein the first de-multiplexing units are respectively associated with one of the locking devices and arranged to respectively buffer data units in the data streams that correspond to specific types. The second de-multiplexing device is coupled to the first de-multiplexing device and includes a plurality of second de-multiplexing units, wherein the second de-multiplexing units are arranged to respectively buffer data units that are buffered by the first de-multiplexing units and correspond to specific channels.