PURPOSE: To measure the consumed current of an electronic circuit performing logic operation within a short time with good accuracy, by adding an acceleration pulse generating circuit controlled by CPU and a reset output circuit to a current measuring circuit.

CONSTITUTION: The current flowing to an electronic circuit 2 from an operational amplifier 1 is detected by a resistor 3 and amplified by a differential amplifier 4 and converted to a digital value by an A/D converter 5 to be taken in CPU6. CPU6 indicates pulse frequency to the pulse generator 7 of an acceleration pulse generating circuit 14 and sets the number of output pulses to a counter 8. The counter 8 opens and closes a gate 9 on the basis of said indication and the pulse outputted is outputted to an acceleration terminal 13 when an acceleration switch 10 is in an ON-state and the reset switch 11 of a reset output circuit 15 applies resetting to the circuit 2. By this method, logic is subjected to acceleration operation in a steady state and a current is measured from the point of time immediately before a logic state changes to the point of time when the steady state is obtained. After this operation is repeated a necessary number of times, the current in the steady state is measured within a short time and multiplied by a time axis in CPU6 to perform operational processing.