To provide the bus type optical data transmitter with simple configuration without attenuation of an optical signal during transmission.

An optical signal sent from a 2nd station Sn-1 to a 1st station Sn via a 1st optical fiber Fn-1 is converted into a 1st electric signal SGn-1,n by a 1st light emitting light receiving element PAn and fed to the 1st station Sn by a reception data input circuit RCn and fed to a 2nd light emitting light receiving element PBn as a 4th electric signal SGn,n+1 by a transmission data output circuit TCn, and sent to a 3rd transmission Sn+1. The optical signal sent from the 3rd station Sn+1 to the 1st station Sn via a 2nd optical fiber Fn is converted into a 3rd electric signal SGn+1,n, by the 2nd light emitting light receiving element PBn and fed to the 1st station Sn by a reception data input circuit RCn and fed to the 1st light emitting light receiving element PAn as the 2nd electric signal SGn,n-1 by the transmission data output circuit TCn and sent to the 2nd station Sn-1.