To provide an amplifier circuit for minimizing mirror effect and for drastically improving gain as compared with conventional technologies.

The amplifier circuit having gain increase effect comprises a first transistor; a first additional transistor, that provides a capacitor on the junction surface between a base electrode and a collector by equipping a floated emitter, connects the base electrode to the base electrode of the first transistor, is formed on the same chip as the first transistor, matches impedance with the first transistor, and has the same amount of mirror capacitor as the first transistor; and an inverter element that is coupled to the collector end of the first transistor, is further coupled to the first additional transistor, is formed on the same chip as the first transistor, and has reverse height and polarity for the output voltage, as compared with those of the first transistor.