1. A board production work method, comprising:a position detection process of detecting an arrangement position of a detection target provided on a printed circuit board; and
a work executing process of subjecting the printed circuit board to predetermined production work based on the detected arrangement position,
wherein the position detection process includes
an image acquisition step of imaging the printed circuit board under multiple imaging conditions and acquiring multiple items of original image data containing luminance values of each pixel arranged in two-dimensional coordinates,
a difference calculation step of using two of the multiple items of original image data as calculation targets, calculating differences between luminance values of pixels with same coordinate values, and acquiring difference image data which is formed of luminance difference values of each of the pixels, and
a position determination step of determining the arrangement position based on the difference image data, and
wherein an inversion calculation step of inverting a magnitude relationship of luminance difference values of each pixel arranged in the two-dimensional coordinates only when a luminance difference value of a pixel in the arrangement position of the difference image data is smaller than a luminance difference value of a pixel in a position other than the arrangement position is included after the difference calculation step.