An optical transmitter includes an optical modulator that includes a first phase shifter for a most significant bit, a second phase shifter for a least significant bit, and a third phase shifter for fine adjustment, the first phase shifter, the second phase shifter, and the third phase shifter are disposed along an optical waveguide, and a drive circuit that includes a first driver that drives the first phase shifter, a second driver that drives the second phase shifter, and a third driver that drives the third phase shifter, wherein a drive polarity of the third driver is adjustable in a positive direction and a negative direction, and the third phase shifter adjusts an amount of phase change of the optical modulator in a positive direction or a negative direction based on a drive voltage inputted from the third driver.