Abstract: A single core optical fiber connector is disclosed in which an optical signal transmitting line between optical fibers is maintained or short-circuited with a low power loss by utilizing a sectional contact of a single core optical fiber. An elastic deformation energy of a polymer material is utilized so as to achieve the sectional contact for minimizing the loss, and precisely machined alignment devices are utilized so as to reduce the misalignment between the optical fibers, thereby improving the assemblability and the economy. The optical fiber sections which are lightly ground on a grinding paper are contacted by using a precisely machined alignment device and by utilizing the elastic deformation energy of the elastic ferrule. This contact is maintained by a coupling between a specially designed plug and an adaptor, thereby forming a structure of an optical fiber connector and an alignment device.