A board work system comprising: a board holding device configured to fixedly hold a board; a first work head and a second work head each configured to perform work with respect to the board held by the board holding device; a first head moving device configured to move the first work head in a first work area; a second head moving device configured to move the second work head in a second work area that is different to the first work area; a first imaging device configured to be moved by the first head moving device along with the first work head; a second imaging device configured to be moved by the second head moving device along with the second work head; a mark arrangement member arranged straddling the first work area and the second work area on which are arranged multiple marks (MA1-MC1) that have a specified relative positional relationship, wherein the board work system is configured to, when performing work with respect to the board, which is a single board held by the board holding device in a state straddling the first work area and the second work area, use the first imaging device to image at least one of the marks of the mark arrangement member that is in the first work area and measure the positions of the imaged at least one marks in the first work area, use the second imaging device to image at least one of the marks of the mark arrangement member that is in the second work area and measure the positions of the imaged at least one marks in the second work area, and, based on the measured positions of the marks (MA1,MC1) in the first work area and the second area, during the work, correct at least one of a position to which to move the first work head by the first head moving device and a position to which to move the second work head by the second head moving device, characterized in that the board work system is further configured to estimate a position of the at least one mark of the mark arrangement member that is in the second work area based on the measured position of the mark in the first work area, and, during the work, correct at least one of the position to which to move the first work head by the first work head moving device and the position to which to move the second work head by the second head moving device based on a deviation between the estimated position and the measured position of the mark in the second work area. a board holding device configured to fixedly hold a board; a first work head and a second work head each configured to perform work with respect to the board held by the board holding device; a first head moving device configured to move the first work head in a first work area; a second head moving device configured to move the second work head in a second work area that is different to the first work area; a first imaging device configured to be moved by the first head moving device along with the first work head; a second imaging device configured to be moved by the second head moving device along with the second work head; a mark arrangement member arranged straddling the first work area and the second work area on which are arranged multiple marks (MA1-MC1) that have a specified relative positional relationship, wherein the board work system is configured to, when performing work with respect to the board, which is a single board held by the board holding device in a state straddling the first work area and the second work area, use the first imaging device to image at least one of the marks of the mark arrangement member that is in the first work area and measure the positions of the imaged at least one marks in the first work area, use the second imaging device to image at least one of the marks of the mark arrangement member that is in the second work area and measure the positions of the imaged at least one marks in the second work area, and, based on the measured positions of the marks (MA1,MC1) in the first work area and the second area, during the work, correct at least one of a position to which to move the first work head by the first head moving device and a position to which to move the second work head by the second head moving device, characterized in that the board work system is further configured to estimate a position of the at least one mark of the mark arrangement member that is in the second work area based on the measured position of the mark in the first work area, and, during the work, correct at least one of the position to which to move the first work head by the first work head moving device and the position to which to move the second work head by the second head moving device based on a deviation between the estimated position and the measured position of the mark in the second work area.