PURPOSE: To obtain a high accuracy current response by constituting a current mirror circuit with a stable NPN-shaped transistor.

CONSTITUTION: A direct current bias power source 7 and a signal source 8 are connected the base for a transistor 1 to constitute a differential circuit and to the base of other transistor 2, the direct current bias power source 7 is connected. A pair of NPN-shaped transistors 3 and 4 in which a collector is respectively connected to the collector of transistors 1 and 2 constitute a current mirror circuit. Current sources 10 and 11 connected to respective collector connecting points has the current quantity larger than the current to flow at a current source 12 and a load resistance 5 is connected to the collector of a transistor 4 at the side, in which the diode of the current mirror circuit is not connected. Thus, the current response of the high accuracy can be obtained.