A laser driving device in the embodiment includes: a laser light source that emits laser light; a light source drive control unit that adjusts a light amount of laser light emitted from the laser light source constant and controls on-off driving of the laser light source; a light amount adjustment element that is disposed in an optical path of laser light emitted from the laser light source and is capable of electrically changing transmittance or reflectance of the laser light that is entered thereinto; and a peak light amount control unit that controls the transmittance or the reflectance of the light amount adjustment element, so as to adjust a peak light amount of the laser light that is output from the light amount adjustment element after having traveled through or having been reflected by the light amount adjustment element.