1. An image acquiring apparatus comprising: micro image acquiring means for acquiring a micro image of a sample by scanning the sample at a predetermined resolution; image pickup condition setting means for setting, for the sample, an image acquiring range corresponding to a range including an object of image acquisition and focus information concerning the image acquisition of the object in the image acquiring range; and micro image acquisition control means for controlling an operation for acquiring the micro image of the micro image acquiring means, wherein the micro image acquiring means has an image pickup device capable of acquiring a one-dimensional image or a two-dimensional image and sets one direction on an image pickup plane in the image pickup device as a scanning direction for acquiring the micro image, the micro image acquisition control means performs control so that a partial image is acquired by scanning the sample in the scanning direction by the image pickup device and a plurality of partial images that become the micro image are acquired by repeating this partial image acquisition a plurality of times while changing an image pickup position along another direction of the image pickup plane, and when at least a first image acquiring range and a second image acquiring range are set as the image acquiring range, the image pickup condition setting means sets corresponding first focus information and second focus information as the focus information, and when a partial image among the plurality of partial images includes mixing of a first region belonging to the first image acquiring range and a second region belonging to the second image acquiring range, the focus information is switched between the first focus information and the second focus information in the respective first region and second region to perform scanning of the sample for acquiring the partial image.