An optical connector for an optical tomographic imaging system for acquiring an optical tomographic image of an object under measurement, the optical connector comprising: a holder unit; a first optical fiber (FBa) fixedly supported by the holder unit and having on one end thereof an end face inclined a given angle (θ1) with respect to a plane perpendicular to its optical axis; a first collimating lens disposed at a given distance from the inclined end face of the first optical fiber (FBa); a mounting unit supported with respect to the holder unit; a second optical fiber (FBb) fixedly attached to the mounting unit, disposed opposite the first collimating lens, and having an end face inclined a given angle (θ2) with respect to a plane perpendicular to its optical axis; and a second collimating lens fixedly attached to the mounting unit and disposed between the first collimating lens and the second optical fiber (FBb) with a given distance from the inclined end face of the second optical fiber (FBb), wherein an optical transmission system comprising the first optical fiber (FBa) and the first collimating lens is disposed symmetrically to an optical transmission system comprising the second optical fiber (FBb) and the second collimating lens with respect to a plane perpendicular to an optical axis, characterized in that the holder unit has a cylindrical projection of which an outer periphery has a tapered shape growing smaller in diameter toward a forward end thereof, and the mounting unit has a cylindrical bore having a tapered inner periphery in contact with the outer periphery of the projection such that the bore of the mounting unit engages with the projection of the holder unit to support the mounting unit with respect to the holder unit, the optical connector comprises a positioning mechanism for fixing a position of the mounting unit with respect to the holder unit in a circumferential direction about an optical axis and fixing a relative position of the inclined end faces of the first optical fiber (FBa) and the second optical fiber (FBb) in a circumferential direction about an optical axis, keeping the distance between the collimating lenses constant, and the positioning mechanism comprises a screw which is formed in part of the outer periphery of the cylindrical projection of the holder unit and a key groove which is linearly formed in the inner periphery of the cylindrical bore of the mounting unit to receive the screw, so that the forward end faces of the first and second optical fibers (FBa, FBb) are placed in a constant positional symmetrical relationship. a holder unit; a first optical fiber (FBa) fixedly supported by the holder unit and having on one end thereof an end face inclined a given angle (θ1) with respect to a plane perpendicular to its optical axis; a first collimating lens disposed at a given distance from the inclined end face of the first optical fiber (FBa); a mounting unit supported with respect to the holder unit; a second optical fiber (FBb) fixedly attached to the mounting unit, disposed opposite the first collimating lens, and having an end face inclined a given angle (θ2) with respect to a plane perpendicular to its optical axis; and a second collimating lens fixedly attached to the mounting unit and disposed between the first collimating lens and the second optical fiber (FBb) with a given distance from the inclined end face of the second optical fiber (FBb), wherein an optical transmission system comprising the first optical fiber (FBa) and the first collimating lens is disposed symmetrically to an optical transmission system comprising the second optical fiber (FBb) and the second collimating lens with respect to a plane perpendicular to an optical axis, the holder unit has a cylindrical projection of which an outer periphery has a tapered shape growing smaller in diameter toward a forward end thereof, and the mounting unit has a cylindrical bore having a tapered inner periphery in contact with the outer periphery of the projection such that the bore of the mounting unit engages with the projection of the holder unit to support the mounting unit with respect to the holder unit, the optical connector comprises a positioning mechanism for fixing a position of the mounting unit with respect to the holder unit in a circumferential direction about an optical axis and fixing a relative position of the inclined end faces of the first optical fiber (FBa) and the second optical fiber (FBb) in a circumferential direction about an optical axis, keeping the distance between the collimating lenses constant, and the positioning mechanism comprises a screw which is formed in part of the outer periphery of the cylindrical projection of the holder unit and a key groove which is linearly formed in the inner periphery of the cylindrical bore of the mounting unit to receive the screw, so that the forward end faces of the first and second optical fibers (FBa, FBb) are placed in a constant positional symmetrical relationship.