Abstract: A light modulator includes a base layer, a metal reflective layer formed on the base layer, a modulation layer of a nonlinear optical crystal formed on the reflective layer, and a conductive pattern layer including a plurality of pattern portions arranged periodically in a first direction and each extending in a second direction, and formed on the modulation layer. The modulation layer changes a reflectance for object light by changing a refractive index when a voltage is applied between the reflective layer and the conductive pattern layer. The light modulator outputs the object light being incident from an upper surface side of the modulation layer, transmitted through the modulation layer, and reflected by the reflective layer to the outside as modulated light with an intensity modulated by the reflectance change.