An optical cable according to the present invention relates to an optical
cable having a construction to enable reduction of a cable outer
diameter, and/or improvement of contained efficiency of coated optical
fibers while an increase of transmission loss in each coated optical
fiber is suppressed. The optical cable has a loose-tube type of structure
constructed by: a tension member; a plurality of tubes stranded together
around the tension member; and an outer sheath covering the outer
periphery of the plurality of tubes. One or more coated optical fibers
are contained in each tube. A ratio of A/B is 6.3 or more but 7.0 or
less, where each coated optical fiber has a mode field diameter A in a
range of 8.6.+-.0.4 .mu.m at a wavelength of 1.31 .mu.m, and where a
fiber cutoff wavelength thereof is B .mu.m.