Abstract: A wide-band amplifier using a plurality of transistors used in transmission, voice, applications video, high-vision in CATV, etc., for example. In the wide band amplifier, an input signal is applied in common across the respective bases and corresponding emitters of the plurality of transistors and the respective output currents are withdrawn from the transistor collectors. Thus, the output currents of the transistors are reduced, possible distortions in the outputs are greatly reduced, the upper operating frequency limit (f.sub.T) is increased to about 3 GHz, and possible distortions in the output currents of the transistors are cancelled by inserting in the input circuit a transistor having the same characteristic as the first mentioned transistors.