To provide a circuit device in which simplification of inspection of the circuit device, reduction of the number of terminals and enhancement of a detecting ratio of non-conforming articles are realized and an operating state of an internal circuit can be easily confirmed even in the case where a specific signal for testing cannot be inputted.

A circuit device is provided with means 2, 3 recording an actual generation state indicating that a predetermined value is actually generated as an output of an internal circuit 1; a means 4 recording a prediction generation state indicating a generation state of the above predetermined value predicted as the output of the internal circuit 1; and a means 5 comparing the above actual generation state with the above prediction generation state and carrying out an output representing whether an action of the internal circuit 1 is normal or not responsive to the comparison result.