Optical circuit

An optical circuit is provided in which electric circuit parts and optical circuit parts are integrated in a stack on a printed substrate. The optical circuit is provided with a lid having a temperature regulation function that uses a temperature control element and an optical fiber block capable of optical input and output. Temperature control of optical circuit elements can be efficiently performed by mounting electric circuit parts and optical circuit parts on a printed substrate in advance by a reflow step using OBO technology and subsequently attaching a lid that includes a temperature control element.