IMAGE CAPTURING APPARATUS AND FOCUSING METHOD THEREOF

In the image capturing apparatus, the optical path difference producing member is disposed on the second optical path. Thereby, the amount of light on imaging an optical image which is focused at the front of an optical image made incident into the first imaging device (front focus) and an optical image which is focused at the rear thereof (rear focus) by the second imaging device can be suppressed to secure the amount of light on image pickup by the first imaging device. Further, in the image capturing apparatus, the first imaging region and the second imaging region on the imaging area of the second imaging device are positioned on the front side of the imaging area in a scanning direction of the sample with respect to the region into which an optical image is made incident which is conjugate to the first optical image made incident into the first imaging device. Thereby, it is possible to obtain in advance a deviation direction of a focus position of the objective lens by a simple constitution.