To provide an optical fiber sensor array having small power dividing loss even in the case of increasing the number of channels of the optical fiber sensor array so as to be unrestricted by the number of channels.

An optical fiber sensor array arranged between a light source and the light receiving side is provided with partial arrays A1, A2, A3 with optical fiber sensors arranged in multiple stages, and the whole array A1+A2+A3 with basic units arranged in multiple stages, with each partial aray as a basic unit. Accordingly, even in the case of increasing the number of channels of the optical fiber sensor array, power dividing loss is small, and the optical fiber sensor array is unrestricted by the number of channels.