DISK DEVICE

PROBLEM TO BE SOLVED: To record an image pickup result even just after the operation of recording start while effectively avoiding increase in power consumption when applying a device to a removable hard disk device recording a video signal and to output a reproduced result even just after the operation of reproduction start while effectively avoiding increase in power consumption. SOLUTION: At the time of recording data which is to be recorded is temporarily held in a buffer memory until the rotary speed of a disk-like recording medium becomes a writing possible rotary speed. At the time of reproduction, data which is held in the buffer memory and is previously read is outputted until the rotary speed of the disk-like recording medium becomes rotary speed by which reproduction can be executed. The data transfer speed of data recorded in the disk-like recording medium is controlled in accordance with the data quantity of data held in the buffer memory.