We proposed many miniature robots using piezos and electromagnets. The robots are small and they can carry small numbers of sensors and actuators.Non-contact measurements of their physical conditions are required.We propose current measurement method of a circuit by using a non-contact thermometer.Since the increase in temperature is proportional to the power consumption, the temperature measurement indicates the current in the circuit.In the preliminary experiment, the current was in proportion to the temperature measured by the non-contact thermometer. The result of the experiment gave good agreement with the value that was obtained by theoretical calculation.