PROBLEM TO BE SOLVED: To prevent performance deterioration due to the deviation of the resonance frequency of a fiber caused by the individual difference or secular change of a device, and to appropriately adjust a drive frequency.SOLUTION: An optical scanning method includes: a resonance frequency detection step (step S02) of detecting the resonance frequency of the top end part of a fiber supported in a swingable manner a drive frequency determination step (step S03) of determining the drive frequency of the top end part of the fiber on the basis of the detected resonance frequency and a scanning step (step S04) of emitting light from the top end part of the fiber, and oscillation-driving the top end part of the fiber by the determined drive frequency to scan the light on an object.
