To provide a hair restoration/growth stimulating device that stably provides a sufficient hair restoration/growth stimulating effect without using ultra-narrow band light, there is provided a hair restoration/growth stimulating device comprising: a casing to be worn on a user's head； and a plurality of light emitting diodes that are attached inside the casing and emit light having a peak wavelength band between 630 nm and 660 nm, both inclusive, and a full width at half maximum between 15 nm and 20 nm, both inclusive, wherein the plurality of light emitting diodes emit the light to directly irradiate the user's head.
