A reading apparatus includes a conveyance roller configured to convey a medium, a reading unit configured to read an image of the medium conveyed by the conveyance roller, a detection unit configured to detect a rotation phase of the conveyance roller, a storage unit configured to store index values, each index value being associated with the rotation phase of the conveyance roller and corresponding to a conveyance amount of the conveyance roller per unit rotation angle, and a timing control circuit configured to select the index value based on a detection result of the detection unit and to control a reading timing of the reading unit based on a result of comparing a cumulative value of selected index values with a threshold corresponding to a reading resolution.