Disclosed are a scanner capable of adjusting the focus distance and an image forming apparatus having the same. The scanner may include a focus adjustment structure that comes into an interfering contact with a scanning unit as the scanning unit moves along a scanning path so as to cause a movement of the scanning unit in the direction perpendicular to the scanning path toward and away from the document to be scanned. With such configuration the focus adjustment can be realized using the scanning movement of the scanning unit along the scanning path.