The present invention provides an optical receiver that enables to vary the sensitivity depending on the transmission speed. The optical receiver provides a photodiode to generate the photocurrent, the pre-amplifier to convert the photocurrent to the voltage signal, the lead pin to supply the bias voltage to the photodiode, and the control block to generate the switching signal for varying the current-to-voltage conversion efficiency and the frequency bandwidth of the pre-amplifier based on the control signal. The control signal is commonly provided from the lead pin through which the bias voltage is applied. The control block interprets the signal applied to the lead pin and generates the switching signal.