A control apparatus for registering a connection state between component devices constituting a distributed optical transmission apparatus in a database includes: a device setting unit which performs setting such that light is output from a component device that is a connection source; and a registration processing unit which acquires a light reception level of each port in each component device on a side receiving the light, identifies a port having a light reception level higher than light reception levels of other ports, and registers a component device having the identified port and the identified port in the database as a connection destination of the component device that is the connection source.