To enable a remarkable shortage of a testing time without lowering a fault detection rate in a counter circuit having a counter to be inspected and a testing circuit cooperated with the counter.

The testing circuit 4 has an operation set means 5 for setting an operation of the counter 2 divided into a plurality of counter blocks 3 at each counter block, and an initial value set means 6 for setting a predetermined initial value to each counter block 3 at each operation set by the means 5, thereby inspecting based on the counter output after each operation.