PURPOSE: To easily confirm the water depth while implementing underwater image pickup.

CONSTITUTION: A display signal generating circuit 16 generates a display video signal for measurement of water depth by a water depth sensor 10. An image pickup circuit 18 generates a video signal of an object. A synthesis circuit 20 synthesizes outputs of a display signal generating circuit 16 and the image pickup circuit 18 and gives the result to a monitor 22 and a recording circuit 24. The water depth is displayed on the monitor 22 together with the object. The recording circuit 24 records the object video image onto a recording medium together with the water depth. A warning generating circuit 30 raises warning when the measured value by the water depth sensor 10 exceeds an allowable value.