A pressure reducing valve including: a valve chamber that is provided in a housing and into which fluid is introduced; a pressure reducing chamber that is provided in the housing and that communicates with the valve chamber via a valve hole of a valve seat provided between the pressure reducing chamber and the valve chamber; and a valve element that is arranged inside the valve chamber and that is configured to be seated on an inner periphery of the valve hole, wherein when the valve element is open, the pressure reducing valve reduces a pressure of the fluid by causing the fluid to move to the pressure reducing chamber via the valve hole, wherein the valve element has a single stage taper portion that is seated on the inner periphery of the valve hole, and the inner periphery of the valve hole includes a first area, a second area and a third area in order from an upstream side of a flow direction of the fluid, characterized in that the first area is provided such that, when the valve element is open, a height of a flow passage defined between the first area and the single stage taper portion of the valve element gradually reduces toward a downstream side of the flow direction, the second area is provided such that a height of a flow passage defined between the second area and the single stage taper portion is constant when the valve element is open and the entire second area contacts the single stage taper portion when the valve element is closed, and the third area is provided such that, when the valve element is open, a height of a flow passage defined between the third area and the single stage taper portion gradually increases toward the downstream side of the flow direction. a valve chamber that is provided in a housing and into which fluid is introduced; a pressure reducing chamber that is provided in the housing and that communicates with the valve chamber via a valve hole of a valve seat provided between the pressure reducing chamber and the valve chamber; and a valve element that is arranged inside the valve chamber and that is configured to be seated on an inner periphery of the valve hole, wherein when the valve element is open, the pressure reducing valve reduces a pressure of the fluid by causing the fluid to move to the pressure reducing chamber via the valve hole, wherein the valve element has a single stage taper portion that is seated on the inner periphery of the valve hole, and the inner periphery of the valve hole includes a first area, a second area and a third area in order from an upstream side of a flow direction of the fluid, characterized in that the first area is provided such that, when the valve element is open, a height of a flow passage defined between the first area and the single stage taper portion of the valve element gradually reduces toward a downstream side of the flow direction, the second area is provided such that a height of a flow passage defined between the second area and the single stage taper portion is constant when the valve element is open and the entire second area contacts the single stage taper portion when the valve element is closed, and the third area is provided such that, when the valve element is open, a height of a flow passage defined between the third area and the single stage taper portion gradually increases toward the downstream side of the flow direction.