Provided is a technique capable of effectively reducing local speckle noise caused by scanning with laser light involving a variation in scanning speed and improving the overall quality of an image.A laser light source emits laser light with an output level Lc corresponding to a display grayscale of a pixel according to a predetermined waveform pattern PT within a pixel display period which is set to increase as a scanning speed Vh is reduced. The waveform pattern PT is set such that a unique relaxation oscillation of the laser light source increases as the scanning speed Vh is reduced. A scanning mirror reflects the laser light emitted from the laser light source in a predetermined scanning order according to its deflection angle so as to be projected onto a projection surface.