PURPOSE: To easily confirm the gain or the like of an analog signal processing circuit by subjecting the test signal, which is added to the image pickup result, to analog signal processing and detecting it.

CONSTITUTION: A system control circuit 14 consisting of a microcomputer which controls whole of a television camera 1 outputs control data CD to a D/A conversion circuit 7 and R, G, and B circuits of a digital signal processing circuit 9 and sets R, G, and B circuits of circuits 6 and 9 to operating states recorded in the memory circuit of the circuit 14. The circuit 14 executes prescribed processing procedures with a fixed period to not only monitor the operation of the whole of the camera 1 but also adjust the gains of R, G, and B circuit of the circuit 6. That is, the circuit 14 takes successive integral results IR, IG, and IB as the input from R, G, and B circuits of a test signal detection circuit 13 after setting the operating states and detects the signal level of a test signal ST, where digital color signals DR, DG, and DB outputted from an A/D conversion circuit 8 are superposed, from these results.