To quickly and precisely inspect a mounted condition of a mounted circuit board and a difference between the objective circuit boards.

This method/device has a control means for imaging an inspection range of a nondefective mounted circuit board, by a camera part, to generate a reference nondefective imaged data, in a pretreatment process, for imaging an inspection range of a plurality of different nondefective mounted circuit boards of the kind same to the nondefective mounted circuit board, by the camera part, to acquire a variation range data indicating a range where the reference nondefective imaged data are dispersed to be varied, in a learning process, for imaging an inspection range of an inspection-objective mounted circuit board, by the camera part, to generate an inspection object imaged data, in an inspection process, for comparing the inspection object imaged data with the reference nondefective imaged data including the variation range data, to extract an inconsistent data, and for determining the quality, based on a size of the inconsistent data.