To provide a polyester fiber excellent in light resistance, free from fall of pile yarn, not causing white blurring and suitable for use of vehicle sheets, etc., for automobiles, electric cars.

This polyester-based spun-dyed conjugate fiber is a core-sheath type conjugate fiber in which the core component is composed of polyethylene terephthalate-based copolyester having ≥80°C glass transition point and containing 8-30 mol% 2,6-naphthalenedicarboxylic acid component copolymerized and the sheath component is composed of polyethylene terephthalate, and a ratio of the sheath component to total weight of fiber is 40-70 wt.% and a coloring agent is contained in an amount of 0.5-3.0 wt.% in the polyethylene terephthalate of the sheath component.