In an image recording apparatus, edge sensors are disposed in front of and behind a recording position on a transport path of printing paper. The edge sensors detect a widthwise position of the printing paper in respective positions upstream and downstream of the recording position. A controller in the image recording apparatus calculates the widthwise position of the printing paper in the recording position, based on detection results from the edge sensors. Thus, the widthwise position of the printing paper in the recording position is identified without the placement of an edge sensor in the recording position on the transport path.