A high-pressure fuel supply pump, comprising: a pump body including a first hole, a second hole and a third hole, said holes (16a,16b,16c) being arranged with increasing cross-sectional area in the order of the first hole, the second hole and the third hole in the axial direction of the plunger, from the upper side toward the lower side, wherein the first hole is configured to form the pressurizing chamber at an inner wall portion, the first hole having a first cross sectional area forming the pressurizing chamber, the second hole communicating with the first hole, being formed on the side opposite to the pressurizing chamber, and having a second cross sectional area larger than the first cross sectional area, and the third hole communicating with the second hole, being formed on the side opposite to the pressurizing chamber, and having a third cross sectional area larger than the second cross sectional area; a flange portion configured to fix the pump body to a high-pressure fuel supply pump mounting portion, a cylinder which is inserted into the second hole of the pump body from a lower side and wherein the pressurizing chamber is formed further above an uppermost end surface of the cylinder; and a spring holding member having an outer peripheral portion press-fitted into the third hole and fixed to the pump body and a holding portion holding a spring portion for biasing the pump body between the outer peripheral portion and the inner peripheral portion; characterized in that a spring-side lowermost end portion of a holding surface of the spring holding member is a spring contact portion and is disposed above a lowermost end portion of the flange portion. a pump body including a first hole, a second hole and a third hole, said holes (16a,16b,16c) being arranged with increasing cross-sectional area in the order of the first hole, the second hole and the third hole in the axial direction of the plunger, from the upper side toward the lower side, wherein the first hole is configured to form the pressurizing chamber at an inner wall portion, the first hole having a first cross sectional area forming the pressurizing chamber, the second hole communicating with the first hole, being formed on the side opposite to the pressurizing chamber, and having a second cross sectional area larger than the first cross sectional area, and the third hole communicating with the second hole, being formed on the side opposite to the pressurizing chamber, and having a third cross sectional area larger than the second cross sectional area; a flange portion configured to fix the pump body to a high-pressure fuel supply pump mounting portion, a cylinder which is inserted into the second hole of the pump body from a lower side and wherein the pressurizing chamber is formed further above an uppermost end surface of the cylinder; and a spring holding member having an outer peripheral portion press-fitted into the third hole and fixed to the pump body and a holding portion holding a spring portion for biasing the pump body between the outer peripheral portion and the inner peripheral portion; characterized in that a spring-side lowermost end portion of a holding surface of the spring holding member is a spring contact portion and is disposed above a lowermost end portion of the flange portion.