A DC-coupled laser drive circuit (1, 2) comprising: a pre-driver (12, 22) for adjusting an amplitude of a differential voltage signal modulated by a data signal (DATA P, DATA N) to obtain a second differential signal (V3n, V3p) at the output of the pre-driver; a main driver (13, 23) which converts, into an electric current signal to be supplied to a laser diode device, said second differential voltage signal (V3n, V3p) whose amplitude has been adjusted by the pre-driver; the main driver comprising a pair of transistors (Q5, Q6) including (a) respective base terminals into each of which the second differential voltage signal (V3n, V3p) whose amplitude has been adjusted by the pre-driver (12, 22) is supplied, (b) the collector terminal of the transistor of the pair of transistors that is connected to the inverted voltage signal (V3n) being connected to the laser diode device without a capacitor provided between the collector terminal and the laser diode device, and (c) respective emitter terminals which are grounded via a constant electric current source; a voltage drop section (14, 24), provided between the pre-driver and a power source for supplying electric power to the pre-driver, in which an amount of a voltage drop is variable; and a voltage drop amount controlling section (16, 26) comprising a pair of resistors (R, R') having identical resistances, each of them connected to the respective base terminal of each transistor of the pair of transistors (Q5, Q6) of the main driver, the pair of resistors determining an average voltage of a non-inverted output (V3p) of and an inverted output (V3n) of the second differential voltage signal (V3n, V3p), the voltage drop amount controlling section configured to control the amount of the voltage drop in the voltage drop section (14, 24) according to the average voltage of the differential voltage signal (V3n, V3p), so as to adjust the amount of electric power supplied by the voltage drop section to the pre-driver. a pre-driver (12, 22) for adjusting an amplitude of a differential voltage signal modulated by a data signal (DATA P, DATA N) to obtain a second differential signal (V3n, V3p) at the output of the pre-driver; a main driver (13, 23) which converts, into an electric current signal to be supplied to a laser diode device, said second differential voltage signal (V3n, V3p) whose amplitude has been adjusted by the pre-driver; the main driver comprising a pair of transistors (Q5, Q6) including (a) respective base terminals into each of which the second differential voltage signal (V3n, V3p) whose amplitude has been adjusted by the pre-driver (12, 22) is supplied, (b) the collector terminal of the transistor of the pair of transistors that is connected to the inverted voltage signal (V3n) being connected to the laser diode device without a capacitor provided between the collector terminal and the laser diode device, and (c) respective emitter terminals which are grounded via a constant electric current source; a voltage drop section (14, 24), provided between the pre-driver and a power source for supplying electric power to the pre-driver, in which an amount of a voltage drop is variable; and a voltage drop amount controlling section (16, 26) comprising a pair of resistors (R, R') having identical resistances, each of them connected to the respective base terminal of each transistor of the pair of transistors (Q5, Q6) of the main driver, the pair of resistors determining an average voltage of a non-inverted output (V3p) of and an inverted output (V3n) of the second differential voltage signal (V3n, V3p), the voltage drop amount controlling section configured to control the amount of the voltage drop in the voltage drop section (14, 24) according to the average voltage of the differential voltage signal (V3n, V3p), so as to adjust the amount of electric power supplied by the voltage drop section to the pre-driver.