Provided is a document reading apparatus capable of surely detecting the document cover open/closed state and the open/close operation, without being affected by the external environment. This document reading apparatus includes a light source, a linear reading device and a document cover. In this document reading apparatus, the light amount value of the light received by the linear reading section while the light source is turned on, and the light amount value of the light received by the linear reading section when the light source is turned off are used to detect the open/closed state and the open/close operation of the document cover, wherein the preparation for printing starts when the document cover has shifted from the open state to the closed state.