A fuel pump for a direct injection system and comprising: a main body; a pumping chamber defined in the main body; a piston, which is mounted in a sliding manner on the inside of the pumping chamber so as to cyclically vary the volume of the pumping chamber; an intake duct, which ends in the pumping chamber; an intake valve, which is arranged along the intake duct; and a flow rate adjustment device provided with a control rod, which is coupled to the intake valve, and with an electromagnetic actuator, which is configured to axially move the control rod; wherein the flow rate adjustment device comprises a containing element, which houses the electromagnetic actuator, has an open end facing the intake valve, and is connected to the main body by means of an annular weld; and wherein the containing element comprises a first cylindrical wall inside which the electromagnetic actuator is arranged, which is in direct contact with the first cylindrical wall; the fuel pump is characterized in that: the containing element comprises a second cylindrical wall, which is coaxial to the first cylindrical wall, has a diameter greater than a diameter of the first cylindrical wall, is arranged around the first cylindrical wall at a non-null distance from the first cylindrical wall, and is connected to the first cylindrical wall by means of a discoidal wall having an outer circular rim integral with the second cylindrical wall and an inner circular rim integral with the first cylindrical wall; and the annular weld is obtained between the main body and the second cylindrical wall of the containing element. a main body; a pumping chamber defined in the main body; a piston, which is mounted in a sliding manner on the inside of the pumping chamber so as to cyclically vary the volume of the pumping chamber; an intake duct, which ends in the pumping chamber; an intake valve, which is arranged along the intake duct; and a flow rate adjustment device provided with a control rod, which is coupled to the intake valve, and with an electromagnetic actuator, which is configured to axially move the control rod; wherein the flow rate adjustment device comprises a containing element, which houses the electromagnetic actuator, has an open end facing the intake valve, and is connected to the main body by means of an annular weld; and wherein the containing element comprises a first cylindrical wall inside which the electromagnetic actuator is arranged, which is in direct contact with the first cylindrical wall; the fuel pump is characterized in that: the containing element comprises a second cylindrical wall, which is coaxial to the first cylindrical wall, has a diameter greater than a diameter of the first cylindrical wall, is arranged around the first cylindrical wall at a non-null distance from the first cylindrical wall, and is connected to the first cylindrical wall by means of a discoidal wall having an outer circular rim integral with the second cylindrical wall and an inner circular rim integral with the first cylindrical wall; and the annular weld is obtained between the main body and the second cylindrical wall of the containing element. the containing element comprises a second cylindrical wall, which is coaxial to the first cylindrical wall, has a diameter greater than a diameter of the first cylindrical wall, is arranged around the first cylindrical wall at a non-null distance from the first cylindrical wall, and is connected to the first cylindrical wall by means of a discoidal wall having an outer circular rim integral with the second cylindrical wall and an inner circular rim integral with the first cylindrical wall; and the annular weld is obtained between the main body and the second cylindrical wall of the containing element.