A light reception device includes: an interferometer that outputs a signal obtained by making an optical phase modulated signal interfere with a reference signal after shifting an optical phase of the optical phase modulated signal by a given amount; a light reception element that receives an output signal from the interferometer and converts the output signal into a light reception current; and a phase controller that controls a control amount in controlling the given amount so that a value of a function, which is calculated based on an amount relating to the light reception current and a change amount of an amount relating to the light reception current against the control amount, becomes an extreme value or 0.