The present invention is to provide an optical transmitter with reduced power consumption. The optical transmitter includes two laser diodes connected in series to each other, one of which is connected in the anode thereof to the first driver, while the other of which is connected in the cathode thereof to the second driver. Further, between the anode of the first laser diode and the cathode of the second laser diode connects an impedance device. In the present invention, the first and second laser diodes, and the impedance device have the substantially same impedance to each other within a concerned frequency range.