In an image read method and device for reading an image on an original, more particularly large size original, pairs of transfer rollers are detachably provided on the insert side and the original discharge side of a platen roller, which is detachably disposed facing a platen glass. Sensors for sensing positions of an original transferred by the transfer roller pairs and the platen roller are provided. Touching and detaching between the transfer roller pairs and the platen roller are sequentially controlled according to the positions of the original as sensed by the sensor.