Fuel flow passage member and fuel injection valve including the same

A fuel flow passage member comprising:

• a first member including
• a first tubular portion that forms a part of a fuel flow passage configured to cause fuel to flow therein,
• a first end portion that is formed at one end of the first tubular portion,
• a first joint surface that is formed in one end surface of the first tubular portion, and
• a first inner diameter enlarged portion that is formed on a side opposite to the first joint surface with respect to the first end portion of the first tubular portion and that has an inner diameter larger than an inner diameter of the first end portion;
• a second member including
• a second tubular portion that forms a part of the fuel flow passage therein,
• a second end portion that is formed at one end of the second tubular portion,
• a second joint surface that is formed in one end surface of the second tubular portion and joined to the first joint surface, and
• a second inner diameter enlarged portion that is formed on a side opposite to the second joint surface with respect to the second end portion of the second tubular portion and that has an inner diameter larger than an inner diameter of the second end portion;
• and
• a welded portion that is in an annular shape and formed by welding the first tubular portion and the second tubular portion to extend radially inward from a radially outside of the first joint surface and the second joint surface, wherein
• an inner diameter of the welded portion is larger than the inner diameter of the first end portion and the inner diameter of the second end portion, and
• an inner periphery portion of the first joint surface and an inner periphery portion of the second joint surface are joined with each other in an axial direction and are located between the first inner diameter enlarged portion and the second inner diameter enlarged portion in the axial direction.