To provide a blade type optical transmitter promoting the efficiency of an installation space and reducing the cost at an introduction initial state.

The blade type optical transmitter includes: an external optical signal interface section; a cross connection section; a plurality of main signal blades 10 to 14 each with an internal optical signal interface mounted thereon; a blade enclosure 15 to which a plurality of the main signal blades are mounted; and a back plane wherein the internal optical signal interfaces of a plurality of the main signal blades are connected in a ring form in the blade enclosure.