An image reading apparatus for use in an office machine includes a first image sensor and a second image sensor. The first image sensor is disposed in an automatic document feeder of the office machine for sensing and reading a first side of a document. The first image sensor includes a first optical module, a first correction element and an elastic sustaining element. The first optical module includes a first light source, a first light-sensing element and a glass surface. The first correction element is arranged at an opposite side of the first optical module. The elastic sustaining element has a free end sustained against the glass surface of the first optical module, thereby facilitating a close contact between the document and the glass surface. The second image sensor is disposed in an office machine main body for sensing and reading a second side of the document.