A filament for artificial hair is excellent in terms of volume and luster and not subject to yarn cracking or yarn breakage. The filament is a filament of a thermoplastic resin, its shape of a cross section in a direction perpendicular to a fiber axis is a multilobal shape having three or more interlobe gap regions, widths W2 of the interlobe gap regions are 10 to 60% of a width W1 of the filament, and depths H2 of the interlobe gap regions are 5 to 30% of a height H1 of the filament.