An image display apparatus having an electronic zoom function. The apparatus includes: imaging means capable of changing a start position of reading an image; in order for at least a part of a predetermined range of the image data to be written at the time of reading the image from a memory, writing means for extracting the predetermined range of the image and writing the extracted image in the memory; reading means for starting to read the image in the memory at the time of reading the image, converting the predetermined range of the image read from the memory into an image of a predetermined resolution, and outputting the image; and when the range of the image read is wider than a range to be expanded, control means for controlling the start position of reading so as to narrow the range of the image to be read.