To provide a data collection system for efficiently collecting a plurality of data without being affected by noise by communication with a simple configuration.

The data collection system comprises a data collection device, and a plurality of data processors connected to the data collection device by cascade connection. Each data processor performs, for example A/D conversion and other data processing individually, and put data obtained by data processing on a data transfer signal, and successively transmits the data to downstream data processors connected in cascade. The top data processor in cascade connection generates a data transfer signal including a data processing period and a communication period for transmitting to the data processor at a later stage. Each of the data processors executes data processing in a data processing period, and transfers data obtained by data processing to the data processor at a later stage in a communication period, on the basis of the data transfer signal.