There is provided a data transmitting system for transmitting data to be processed through a TCP/IP-based network. The data transmitting system includes a first device having an identification information obtaining system that transmits first data through the network using a first multicast address, and a data transmitting system that transmits the data to be processed through the network using a second multicast address. The data transmitting system further includes a second device having an identification information transmitting system that transmits second data containing the identification information of the second device through the network using a third multicast address, and a data receiving system that receives the data to be processed.