-1- A coated optical glass fiber consisting of a glass fiber for light transmission and at least one coating layer made of a UV-curing resin. The outermost coating layer is made of a UV-curing resin having a Young's modulus of at least 100 kg/mm2 and a change of cure shrinkage degree of 1% or less after The Young's modulus reaches one tenth of the end Young's modulus. The optical glass fiber has improved lateral pressure characteristics and a low transmission loss.