An apparatus and method for transmitting broadcast signal to which channel bonding is applied are disclosed. The apparatus according to the present invention includes an input formatting unit configured to generate baseband packets corresponding to a plurality of packet types using data corresponding to a physical layer pipe; a stream partitioner configured to partition the baseband packets into a plurality of partitioned streams corresponding to the plurality of packet types; BICM units configured to perform error correction encoding, interleaving and modulation corresponding to the plurality of partitioned streams, respectively; and waveform generators configured to generate RF transmission signals corresponding to the plurality of partitioned streams, respectively.