A document reading apparatus includes a document supporting portion, a conveyance portion, a driving motor, an image reading unit, and a control portion. The control portion is configured to execute a high speed mode in which the conveyance speed is set to a first conveyance speed and a low speed mode in which the conveyance speed is set to a second conveyance speed slower than the first conveyance speed. When the control portion executes the low speed mode, if the document has a first thickness, the control portion is configured to execute a first low speed mode where a first drive speed is set to the driving motor. If the document has a second thickness thicker than the first thickness, the control portion is configured to execute a second low speed mode where a second drive speed faster than the first drive speed is set to the driving motor.