the driver controller 12 is activating the drive unit by adoption of the second activation method the system controller 22 detects this command and passes on the command to the memory controller 21 receiving this command the memory controller 21 starts an operation to store the image taking signal in the memory circuit 20 since the activation step according to the second activation method can be completed in a relatively short period of time as described above the activation step according to the second activation method can be completed before the amount of the image taking signal stored in the memory circuit 20 exceeds the first predetermined quantity thus the memory controller 21 may start an actual recording operation as soon as the amount of the image taking signal stored in the memory circuit 20 exceeds the first predetermined quantity in the same way as that explained earlier by referring to the time charts shown in fig2 without taking the operation of the driver controller 12 into consideration thereafter the amount of information stored in the memory circuit 20 gradually decreases and intermittent recording operations are carried out repeatedly in the same way as that explained earlier by referring to the time charts shown in fig2 in addition if the user enters a command to stop the recording operation.