1. An endoscope apparatus, comprising: an image pickup device in which a plurality of pixels are arranged in a matrix shape, and which starts sequential exposure by at least one of scan lines with respect to the plurality of pixels to generate image data, and outputs image data for each of the scan lines in an order of starting exposure; a detection device that detects whether or not an image region at which a part of an object region is edged along a direction parallel to the scan lines in a state that is different to a case where a plurality of the scan lines are simultaneously exposed exists in a frame image due to differences of exposure timings for each of the scan lines of the image pickup device based on an image feature amount in the frame image that is obtained from the image data for each of the scan lines that is outputted from the image pickup device; and an exposure control device that changes an exposure time of each of the scan lines by the image pickup device simultaneously for all of the scan lines if the detection device detects the image region.