PURPOSE: To reduce current consumption as low as possible by controlling the driving timing of a circuit (disk driving means) requiring a large current consumption even when a long signal processing time is required for a signal processing means.

CONSTITUTION: A subject obtained from a photographing lens 10 is formed on an image pickup element 11. An electric signal outputted from the element 11 is amplified and converted into a digital signal through an amplifier 14 and an A/D converter 15 and then the digital signal is temporarily written in a buffer memory 16. A digital signal processing circuit 17 executes data compression and encoding and writes the processed result in a buffer memory 19. At the same timing as writing in the memory 19, a spindle motor 7 starts to be rotated by a servo control circuit 6. When a disk 21 is turned to a stable state, the state is detected by a stable state detector 12. A system control part 1 reads out data from the memory 19 and writes the read contents in the disk 21.