An optical scanning device of the invention includes: a substrate; torsion bar portion which is connected to the substrate; a mirror portion which is supported by the torsion bar portion; a drive source which causes the substrate to oscillate; and a light source which projects light onto the mirror portion, where the mirror portion resonates and vibrates in accordance with a vibration imparted to the substrate by the drive source, and the direction of reflection light from the light projected onto the mirror portion from the light source changes in accordance with the vibration of the mirror portion, and a spring constant in a longitudinal direction of the torsion bar portion supporting the mirror portion is distributed along the longitudinal direction of the torsion bar portion.