There is provided a data updating method of a circuit board work system capable of obtaining a reduction in transfer time while reliably transferring changed content of data relating to a work target circuit board between a database server and a circuit board working machine. In an electronic component mounting system 10, when a change in a recipe (setting data) for a control computer 51 are input in any one of a plurality of circuit board working machines such as component mounting machines 14, 16, and the like, the control computer 51 reports changed content to a host computer 82 (S7). The host computer 82 which receives the report updates the data which is stored in the DB server 81 based on the changed content of the recipe (S10). The control computer 51 which receives input of the change in the recipe executes a process in which only the partial data which is updated by the host computer 82 is acquired among the data items which are stored in the DB server 81 (S12).
