A work system includes multiple work devices aligned along a board conveyance line, a replenishing device having a sensor for detecting presence or absence of an interfering object and configured to move in parallel with the board conveyance line while detecting the presence or absence of the interfering object by the sensor to replenish necessary members to the multiple work devices, and a draw-out device configured to draw out at least one of the multiple work devices in a direction orthogonal to a direction along the board conveyance line. When a draw-out request for the work device is made, the replenishing device performs an automatic draw-out process of moving to a position in which a draw-out position of the work device to be pulled forward is included within a detection range of the sensor, so as to determine whether the interfering object is detected by the sensor.