A fan rotor blade includes a blade body constructed of a composite material, a blade root integrally formed at a base end of the blade body by the composite material, and a sheath attached to a leading edge of the blade body so as to extend in a span direction. The sheath includes a sheath main body and a pair of joint flanges, and is segmented into a sheath base segment and a sheath top segment. The sheath top segment smoothly continues from the sheath base segment, and has a longer length than a length of the sheath base segment along a span direction. A sheath length of the sheath main body at an assumed impact position that is a radially outermost position on the sheath top segment to be contacted with an obstacle suctioned into the engine case is not shorter than 10 %chord and not longer than 60 %chord. A sheath length of the sheath along an end edge of the fan rotor blade is not shorter than 40 %chord. The fan rotor blade possesses sufficient impact resistance and can be simplified and light-weighted.