A light projecting device of the present invention includes: a light source unit including a laser element for emitting light, a light converging lens for converging the light emitted from the laser element, and a light emitting section for emitting light upon receipt of the light converged by the light converging lens; and a reflector for projecting light emitted from the light source unit. The apparatus includes a diagnostic monitor that allows patients to easily, quickly and reliably enter information about daily health activity. This structure uses only 12 transistors, The input can be coupled directly to a VCO output, and provides minimum loading, as each VCO output is connected to only two transistors.