An optical communication device includes a planar optical waveguide, a circuit board, a light emitting element, and a light receiving element. The circuit board includes a mounting surface. Both the light emitting element and the light receiving element are supported on the mounting surface. The planar optical waveguide is buried in the circuit board. The planar optical waveguide includes a first sloped surface and a second sloped surface respectively on two opposite ends of the planar optical waveguide. The mounting surface defines a first light guide hole aligning with the first sloped surface and a second light guide hole aligning with the second sloped surface. The light emitting element is aligned with the first sloped surface through the first light guide hole. The light receiving element is aligned with the second sloped surface through the second light guide hole.