IMAGE ACQUISITION DEVICE AND METHOD AND SYSTEM FOR CREATING FOCUS MAP FOR SPECIMEN

An image acquisition device 1 reciprocates a focal position of an objective lens 25 with respect to a sample S in the optical axis direction of the objective lens 25, while moving a field position V of the objective lens 25 with respect to the sample S. This makes it possible to acquire contrast information of image data at the field position V of the objective lens 25 sequentially as the field position V moves with respect to the sample S. The image acquisition device 1 acquires the image data by the rolling readout of the image pickup element 6 according to the reciprocation of the focal position of the objective lens 25. This stabilizes the number of pieces of focus information calculated for each scan of the focal position of the objective lens 25. Therefore, the focus map can be produced rapidly and accurately.