A transport stream (TS) demultiplexer has a TS input switch unit and an output switch unit, whereby inputs and outputs can be selected as desired, external output can be easily changed by changing selected information of the TS input switch unit and the output switch unit, without changing inputs. Therefore, the TS demultiplexer receives a plurality of TSs such as MPEG-2 TSs and DSS TSs, and can selectively demultiplex the TSs, and particularly, the TS demultiplexer can store the TSs in a storage medium such as a hard disc drive, or it can easily transmit the TS data over an IEEE1394 bus or a PCI bus.