There is provided a board work machine (a component mounting machine) including a data registration section for registering in advance multiple data (ultra-high precision data, high precision data, normal precision data) for each characteristic of a member constituting a base material for a circuit board in accordance with the type and characteristic of the member; a work performing section (a part camera) for performing work using the member or performing work on the member while selecting one item of data from the multiple data for reference; and an automatic data switching section for automatically switching among the multiple member data that the work performing section refers to in accordance with the performing situation of the work performed by the work performing section.