Modified cross-section fibers for artificial hair having an improved bulkiness and a soft feeling as compared with conventional fibers for the artificial hair, comprising synthetic fibers, the synthetic fiber having a cross-section comprising one central connecting portion and projections extended in three directions from the central connecting portions, wherein at least one of the three projections is most narrowed at a portion where it is nearer from a top edge of the projection than 1/2 of a length R from a center of the central connecting portion to the top edge of the projection, a ratio of W1/W2 wherein W1 is a width of the widest portion in a portion where it is nearer from the top edge than the most narrowed portion, and W2 is a width of the most narrowed portion is 1.05 to 2.0, and a ratio of R/W1 wherein R and W1 are the same as defined above is from 1.10 to 5.0.