Optical fiber ribbon and slotless optical cable

An optical fiber ribbon, comprising:

• a plurality of single-core coated optical fibers arranged in parallel;
• and
• a tape resin layer integrally coating the plurality of single-core coated optical fibers and intermittently coupling together adjacent ones of the plurality of single-core coated optical fibers, wherein
• the tape resin layer includes, at a portion coating the plurality of single-core coated optical fibers, a thick-walled part and a thin-walled part along a longitudinal direction of the plurality of 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, and
• 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.