A rubber extrusion die comprising: an inflow opening section through which rubber extruded from a rubber extruder flows; a forming opening section which forms rubber inflowing from the inflow opening section and which discharges the rubber as a rubber member having a predefined cross-sectional shape; and a rubber flow path extending from the inflow opening section to the forming opening section in a forward rubber-extruding direction, the cross-sectional area of the flow path decreasing in the forward rubber-extruding direction, wherein in a vertical cross section and/or a horizontal cross section in the rubber-extruding direction of the rubber flow path, a profile line of an inner wall surface along the rubber flow path passes through an area outside a reference line which is a straight line between a rear end point P1, where the inflow opening section intersects the profile line, and a front end point P2, where the forming opening section intersects the profile line, which passing results in a larger cross-sectional area of the rubber flow path than that obtained by the reference line, wherein the profile line of the inner wall surface includes a dividing point P3 which divides an area between the front end point P2 and the rear end point P1 into a front area and a rear area; a profile line of the front area consists of a front inclined line portion which linearly extends from the front end point P2 to the dividing point P3, and a profile line of the rear area consists of a rear inclined line portion which linearly extends from the dividing point P3 to the rear end point P1; and in the front inclined line portion, a distance M in the vertical direction of an interval between the front end point P2 and the dividing point P3, is equal to or larger than a distance N in the rubber-extruding direction of the interval, characterized in that a maximum distance (Tmax) from the reference line to the profile line is equal to or larger than 0.4 times of a distance (La) from the dividing point P3 to the front end point P2 in the rubber-extruding direction. an inflow opening section through which rubber extruded from a rubber extruder flows; a forming opening section which forms rubber inflowing from the inflow opening section and which discharges the rubber as a rubber member having a predefined cross-sectional shape; and a rubber flow path extending from the inflow opening section to the forming opening section in a forward rubber-extruding direction, the cross-sectional area of the flow path decreasing in the forward rubber-extruding direction, wherein in a vertical cross section and/or a horizontal cross section in the rubber-extruding direction of the rubber flow path, a profile line of an inner wall surface along the rubber flow path passes through an area outside a reference line which is a straight line between a rear end point P1, where the inflow opening section intersects the profile line, and a front end point P2, where the forming opening section intersects the profile line, which passing results in a larger cross-sectional area of the rubber flow path than that obtained by the reference line, wherein the profile line of the inner wall surface includes a dividing point P3 which divides an area between the front end point P2 and the rear end point P1 into a front area and a rear area; a profile line of the front area consists of a front inclined line portion which linearly extends from the front end point P2 to the dividing point P3, and a profile line of the rear area consists of a rear inclined line portion which linearly extends from the dividing point P3 to the rear end point P1; and in the front inclined line portion, a distance M in the vertical direction of an interval between the front end point P2 and the dividing point P3, is equal to or larger than a distance N in the rubber-extruding direction of the interval, characterized in that a maximum distance (Tmax) from the reference line to the profile line is equal to or larger than 0.4 times of a distance (La) from the dividing point P3 to the front end point P2 in the rubber-extruding direction.