To measure the supply voltage drop by a simple method with high accuracy without appreciably increasing the chip size of an integrated circuit.

This integrated circuits includes oscillation circuits 4A to 4E which are arranged in prescribed positions of the integrated circuit 1 to measure the supply voltage drop, and in which oscillation frequencies f of output signals SOA to SOE change according to the drop of the supply voltage Vdd at a prescribed position in the operation time of the integrated circuit 1, and an output part (e.g., an I/O pad for measurement arranged at an I/O circuit part 3) which outputs an output signal of the oscillation circuit or a signal SO according to the output signal to the external to measure the supply voltage drop.