The present invention provides a two-layer structure colored optical fiber which includes a colored secondary coating layer improved in collectability and separability. The two-layer structure colored optical fiber in an embodiment of the present invention includes a glass optical fiber, a primary coating layer coating the glass optical fiber, and a colored secondary coating layer coating the primary coating layer. The secondary coating layer has such characteristics that a surface cure percentage is 99% or more at an infrared absorption peak of a wave number of 1407 cm.sup.1 and a surface kinetic friction force in Knot Test is less than 0.075 N.

A resin composition for optical fiber coating contains a photopolymerizable compound and a photopolymerization initiator, in which the photopolymerizable compound contains a di(meth)acrylate having an oxypropylene group and a di(meth)acrylate having an oxyethylene group, and a mass ratio of a content of the oxypropylene group with respect to a content of the oxyethylene group in the photopolymerizable compound is 0.01 or more and 2.00 or less.

A resin composition for optical fiber coating contains a photopolymerizable compound and a photopolymerization initiator, in which the photopolymerizable compound contains a di(meth)acrylate having an oxypropylene group and a di(meth)acrylate having an oxyethylene group, and a mass ratio of a content of the oxypropylene group with respect to a content of the oxyethylene group in the photopolymerizable compound is 0.01 or more and 2.00 or less.