The present invention provides a long-range surface plasmon optical waveguide sensor which has a reduced loss of an electromagnetic wave, an increased sensitivity and limitation of detection and a high analysis speed, and enables fabrication of a sensor of various sizes such as a small-sized or lightweight system, etc. To this end, the long-range surface plasmon optical waveguide sensor, comprising: a sensor section, wherein the sensor section comprises a substrate, a first dielectric layer stacked on the substrate, a metal thin film stacked on the first dielectric layer, a second dielectric layer stacked on the metal thin film and having a channel penetratingly formed therein in such a fashion that the top surface of the metal thin film is partially exposed into the channel, a metal strip stacked on the second dielectric layer in such a fashion that the underside thereof is partially exposed into the channel, and a third dielectric layer stacked on the metal strip; a light source section for inducing a surface plasmon resonance between the metal thin film and the metal strip; and a detection section for detecting and analyzing a change of light according to the surface plasmon resonance.