An optical transmitter includes a light-emitting element, a driving circuit, a temperature detection unit, a storage device and a control circuit. The driving circuit causes, based on an input signal, the light-emitting element to emit an optical signal having a pulse shape. The temperature detection unit detects an ambient temperature of the light-emitting element. The storage device stores temperature characteristics information of the light-emitting element. The control circuit controls the driving circuit based on the ambient temperature detected by the temperature detection unit and the temperature characteristic information stored in the storage device, so that an extinction ratio of the optical signal having the pulse shape becomes substantially constant.