A laser control unit, a laser control circuit and a laser-power adjustment method are provided which are capable of controlling laser power precisely, even if an error is produced in the duty of an optical pulse. A light-receiving element 101 converts the optical pulse into an electric signal and outputs a photo-detection signal; an LPF 114 calculates the average value of the optical pulse, based on the photo-detection signal; a DSP 124 calculates a light-emission power value, based on the average value of the optical pulse and the duty of the optical pulse, and calculates the difference between the light-emission power value and a target power value; an EP-ROM 160 stores a correction value for correcting a calculation which is executed by the DSP 124; the DSP 124 corrects the calculation, based on the correction value, and controls an electric-current value which is supplied to a semiconductor laser 150, based on the calculation result which is obtained from the correction; and a laser drive circuit 40 drives the semiconductor laser 150, based on the electric-current value.