A liquid droplet measurement apparatus has: a first laser light source emitting a laser light; a first optical device which makes, in terms of a beam cross-section of the laser light, a beam width in a direction perpendicular to a direction of ejection of a liquid droplet, greater than a beam width in the direction of ejection of the liquid droplet, and makes light intensity of the laser light fall within a prescribed range within a range where variation in a position of the liquid droplet occurs in the direction perpendicular to the direction of ejection of the liquid droplet, at a position where the laser light from the first laser light source is irradiated onto the liquid droplet ejected; a first light receiving device which receives the laser light that has been irradiated onto the liquid droplet by the first optical device and generates a determination signal; and a first liquid droplet characteristics calculation device which calculates at least one of a volume of the liquid droplet and a velocity of the liquid droplet, from the determination signal generated by the first light receiving device.