A valve stem seal comprising: a reinforcement ring having a tubular body section; and a rubber-like elastic body which is integrally provided with the reinforcement ring, the valve stem seal being configured to be fixed to a valve stem guide that guides a valve stem, wherein the rubber-like elastic body includes: a seal section which is slidable on the valve stem; and a fitting section which is provided on an inner peripheral surface of the body section and which is configured to be fitted and fixed to the valve stem guide, an inner peripheral surface of the fitting section is provided with a plurality of annular seal protrusions (25, 26), each including a first inclined surface (25a, 26a) having a diameter that increases from a radially inward tip toward the seal section and a second inclined surface (25b, 26b) having a diameter that increases from a radially inward tip toward a side opposite to the seal section, characterized in that among the plurality of seal protrusions (25, 26), at least one first seal protrusion arranged on the seal section side is configured so that an inclination of the second inclined surface is smaller than that of the first inclined surface, and among the plurality of seal protrusions (25, 26), at least one second seal protrusion arranged on a side opposite to the seal section with respect to a region where the first seal protrusion is arranged is configured so that an inclination of the first inclined surface is smaller than that of the second inclined surface. a reinforcement ring having a tubular body section; and a rubber-like elastic body which is integrally provided with the reinforcement ring, the valve stem seal being configured to be fixed to a valve stem guide that guides a valve stem, wherein the rubber-like elastic body includes: a seal section which is slidable on the valve stem; and a fitting section which is provided on an inner peripheral surface of the body section and which is configured to be fitted and fixed to the valve stem guide, an inner peripheral surface of the fitting section is provided with a plurality of annular seal protrusions (25, 26), each including a first inclined surface (25a, 26a) having a diameter that increases from a radially inward tip toward the seal section and a second inclined surface (25b, 26b) having a diameter that increases from a radially inward tip toward a side opposite to the seal section, characterized in that among the plurality of seal protrusions (25, 26), at least one first seal protrusion arranged on the seal section side is configured so that an inclination of the second inclined surface is smaller than that of the first inclined surface, and among the plurality of seal protrusions (25, 26), at least one second seal protrusion arranged on a side opposite to the seal section with respect to a region where the first seal protrusion is arranged is configured so that an inclination of the first inclined surface is smaller than that of the second inclined surface. a seal section which is slidable on the valve stem; and a fitting section which is provided on an inner peripheral surface of the body section and which is configured to be fitted and fixed to the valve stem guide, an inner peripheral surface of the fitting section is provided with a plurality of annular seal protrusions (25, 26), each including a first inclined surface (25a, 26a) having a diameter that increases from a radially inward tip toward the seal section and a second inclined surface (25b, 26b) having a diameter that increases from a radially inward tip toward a side opposite to the seal section, characterized in that among the plurality of seal protrusions (25, 26), at least one first seal protrusion arranged on the seal section side is configured so that an inclination of the second inclined surface is smaller than that of the first inclined surface, and among the plurality of seal protrusions (25, 26), at least one second seal protrusion arranged on a side opposite to the seal section with respect to a region where the first seal protrusion is arranged is configured so that an inclination of the first inclined surface is smaller than that of the second inclined surface.