An electro-optic device is provided with a substrate, an optical waveguide formed of a lithium niobate film with a ridge shape on the substrate, and an electrode that applies an electric field to the optical waveguide. The optical waveguide includes a modulation waveguide provided in an electric field application region applied with the electric field and having a thickness of 1 μm or larger and a bent waveguide provided in a region other than the electric field application region and having a curvature radius of 16 μm or larger and 80 μm or smaller.