PURPOSE: To accurately set the input-to-output ratio of a current mirror circuit, by connecting a DC amplifier of one time of gain between the input terminal of the current mirror circuit and common base of transistors.

CONSTITUTION: The bases and emitters of transistors 1 and 2 are commonly connected with each other, respectively, and the collector of the transistor 1 is connected with an input terminal 3, and then, the collector of the transistor 2 is connected with an output terminal 4. A DC amplifier 11 of one time of gain is connected to the input terminal 3 and the common base of the transistors 1 and 2. It is possible to make the bias current of an input terminal 12 sufficiently small to an input current and the base current of the transistors 1 and 2 is absorbed by the output terminal of the amplifier 11 and gives no influence to the input current.