Image reading device and method for the same

When an image object is read using a camera including a line sensor having pixels arrayed in a line, a relative-movement-detecting section detects a movement of a transfer head holding the object in X direction relative to the camera. The detecting section outputs a movement-detecting signal to a camera-controller every time the object moves a given distance corresponding to a scanning space in X direction. The camera-controller controls a pixel-selecting circuit according to the movement-detecting signal and outputs an image signal from pixels selected based on pixel-selecting information. As a result, even if a moving mechanism of the transfer head has an error, a resolution becomes stable and an exact image is obtainable.