The optical device (100) includes a first substrate (10), a second substrate (20), and an optical layer (30). The first substrate includes a first electrode (11) and a second electrode (12) configured to be provided with mutually different electrical potentials within a pixel. The optical layer may include a medium (31) and a plurality of shape-anisotropic particles (32) dispersed in the medium. At least one of the first electrode and the second electrode may include a plurality of comb teeth portions (11a, 12a) arranged at predetermined intervals along the first direction (D1). When an electric potential difference is applied between the first electrode and the second electrode, the pixel may be configured to have an electrical field distribution in which a strong electric field region having a stronger field intensity than another region is periodically formed parallel to the surface of the optical layer along a second direction (D2) orthogonal to the first direction.