Image reading apparatus

An image reading apparatus comprising:

• a transport unit which transports a document;
• a reading unit which reads an image of the document which is transported by the transport unit;
• and
• a control unit which generates image data as data of the image which is read by the reading unit,
• wherein, as operation modes for performing reading in the reading unit, there are a first reading mode for reading a document having a first thickness being conveyed by the conveying unit and a second reading mode in which a document having a second thickness that is thinner than the document having the first thickness and being conveyed by the conveying unit is read;
• In the first reading mode, the control unit causes the reading unit to read an image from a document conveyed by the conveying unit at a speed corresponding to a required resolution, and generates image data of the image read by the reading unit, In the second reading mode, the control unit transports the document so that becomes a slower than in the first reading mode, and read the document, and generates image data of an image having the same resolution as in the first reading mode is generated.