To provide an optical communication device suitable for the transmission of a high-frequency signal. An optical communication device includes a first substrate having a light-emitting element or a light-receiving element on one side of the first substrate; a second substrate having an electronic circuit to perform operation control of the light-emitting element or the light-receiving element; and a flexible substrate which connects the section between the light-emitting element or the light-receiving element and the electronic circuit while achieving impedance matching.