Abstract: An optical fiber ribbon includes a plurality of single-core coated optical fibers arranged in parallel, and a resin layer integrally coating the plurality of single-core coated optical fibers and intermittently coupling together adjacent ones of the single-core coated optical fibers. The resin layer includes, at a portion coating the single-core coated optical fibers, a thick-walled part and a thin-walled part along a longitudinal direction of the single-core coated optical fibers, the thick-walled part being formed to have a thickness equal to or greater than ½ of a maximum thickness, the thin-walled part being formed to have a thickness of less than ½ of the maximum thickness. When a length of the thick-walled part in the longitudinal direction is denoted by “a” and a length of the thin-walled part in the longitudinal direction is denoted by “b,” 4:6<b:a<8:2 is satisfied.

Abstract: Disclosed is an optical fiber ribbon (1) in which a plurality of single-core coated optical fibers (11-22) are intermittently connected or separated in a length direction and a width direction while being connected every two cores. The optical fiber ribbon (1) satisfies conditional expressions [1], [2] when the length in the longitudinal direction of a connection portion (3) is denoted by A, the length in the longitudinal direction of a non-connection portion (5) in which separation portions (4) adjacent to each other overlap when viewing the separation portions (4) in the width direction is denoted by C, and the periodic interval in the longitudinal direction between the connection portions (3) is denoted by P.