A disk nearly constant in recording density from the outer circumference to the inner circumference of the disk, such as CLV and M-CAV format, is rotated at a constant angular velocity to read out information, and the information being read in at a varying read transfer speed depending on the position on the disk from the optical pickup is stored once in a buffer memory. The information stored in the buffer memory is sent out at a constant send transfer speed. When reproducing from a disk-shaped recording medium nearly constant in recording density in the inner and outer circumference, the disk information is read at a constant rotating angular velocity, and the information varying in read transfer speed depending on the disk position is outputted at a constant send transfer speed suited to the reproduction of information such as voice and picture. The host computer or the like for controlling the apparatus is not required to distinguish the type of medium or recording format, or perform processing such as control of the transfer speed. Furthermore, when outputting the stored information, means for setting the send transfer speed by an external device or switch inside the apparatus is provided. By this means, the information can be reproduced at a transfer speed suited to the content of the information being handled.