An information reading apparatus has a feature that, when a disc on which data is recorded by a CLV system is read out by a CAV system, a transfer rate is changed in accordance with an amount of data recorded on the disc and the data can be efficiently read out in a short time. In an information reading apparatus arranged such that data read by rotating at a constant angular velocity a disk-shaped recording medium on which data is recorded at a constant linear velocity is transmitted to an external apparatus through a buffer memory, there is provided a setting unit for setting a rotational angular velocity of the disk-shaped recording medium in a manner such that a transfer rate when the information read at a predetermined radial position excluding the outermost peripheral portion in the information recording region of the disk-shaped recording medium is transferred to the buffer memory is equal to the maximum sustain transfer rate at which the information reading apparatus can perform the reading operation.