Two-Member Fixing Structure and High-Pressure Fuel Supply Pump

A two-member fixing structure that fixes a first member having a cylindrical inner circumferential surface and a second member having a cylindrical outer circumferential surface, wherein

• the second member includes a curved surface portion at one end of the outer circumferential surface in a direction along a center line, the curved surface portion being formed by a curved surface of which a diameter reduces so as to be convex outward in a radial direction as being away from the outer circumferential surface along the center line with the one end of the outer circumferential surface as a start point,
• in a state where the second member is fixed to the inner circumferential surface of the first member, the first member includes a pressed surface formed by pressing a peripheral edge portion of the inner circumferential surface of the first member, and a plastically deformed portion plastically deformed inward of the outer circumferential surface of the second member in the radial direction,
• a circle intersects with the curved surface portion, when the circle is drawn with a radius being a length of a line segment connecting the start point of the curved surface portion and a radially outer end point of the pressed surface of the first member, while the radially outer end point of the pressed surface is the center of the circle, and
• an angle formed between a tangent line that is in contact with the curved surface portion at an intersection point between the circle and the curved surface portion and a line perpendicular to the center line is larger than 0°.