A device for reading out an optical code includes a camera, an image memory for storing images taken by this camera, and an image processor for decoding an optical code contained in an image taken by the camera. A plurality of images are obtained continuously with the camera under specified image-taking conditions in response to a specified image-taking command, and the obtained images are stored on the image memory. The images stored in the image memory are sequentially selected one at a time in a specified order, and the image processor makes an attempt to decode an optical code contained in the selected image. Results of decoding are outputted if the attempt to decode any of the stored images is successful. The interval at which the images are taken is changed according to the number of images successfully decoded taken continuously in the past.