Abstract: A light modulation device includes a lithium niobate light modulator, an amplifier, and a bias control circuit. The lithium niobate light modulator modulates light from a light source in accordance with an input electrical signal, and outputs the modulated light. The lithium niobate light modulator includes a terminal for terminating the electrical signal. The amplifier amplifies the electrical signal to a level where it can drive the lithium niobate light modulator, and outputs the amplified signal to the lithium niobate light modulator. The amplifier includes an amplifying element at an output stage. A bias voltage of the amplifying element is set by externally supplied DC voltages. The bias control circuit supplies the DC voltages to the amplifying element, and a DC operating voltage to the terminating terminal of the lithium niobate light modulator to set a modulation operating point of the lithium niobate light modulator.