An optical transmitter includes: a modulating unit that modulates an optical signal based on an electric signal; a first detecting unit that detects a first variation width of a maximum output of the modulated optical signal; a second detecting unit that detects a second variation width of a minimum output of the modulated optical signal; a comparing unit that performs a comparison of the first variation width and the second variation width; and an adjusting unit that adjusts a bias potential of the electric signal based on a result of the comparison.