An engine intake duct includes an upstream side linear portion, a bend portion, a downstream side linear portion, and a fin that rises from an inner surface of the bend portion on an inner side in a bend direction. A fin tip portion is located in the bend portion, and a fin rear end portion is located in the bend portion or the downstream side linear portion, and the fin includes a tip side inclined surface, a rear end side inclined surface, and a rear end surface that is a steep wall extending from a rear end of the rear end side inclined surface to the fin rear end portion. At least a part of a top of the tip side inclined surface of the fin is formed along an extension line of an inner surface of the upstream side linear portion toward the bend portion.