Ferritic stainless steel sheet having excellent brazability, heat exchanger, ferritic stainless steel sheet for heat exchangers, ferritic stainless steel, ferritic stainless steel for members of fuel supply systems, and member of fuel supply system

A ferritic stainless steel comprising, by mass %:

• C:
• 0.03% or less;
• N:
• 0.002% or more and 0.05% or less;
• Si:
• more than 0.1% and 1% or less;
• Mn:
• 1.2% or less;
• Cr:
• 15% or more and 23% or less;
• Nb:
• 8(C+N)+0.1% or more and 0.8% or less;
• and
• Al:
• 0.002% or more and 0.1% or less,
• with a balance being Fe and inevitable impurities,
• wherein a film satisfying Expressions 2 and 3 is formed in a surface thereof,
• df×Crf+5(Sif+3Alf)≤2.0 (Expression 2)
• 0.18≤Crf≤0.5 (Expression 3)
• in Expression 2, df represents a thickness of the film in terms of nm, Sif represents a Si cationic fraction in the film, and Alf represents an Al cationic fraction in the film, and in Expressions 2 and 3, Crf represents a Cr cationic fraction in the film,
• wherein the ferritic stainless steel has a brazing filler spreading coefficient of 2 or more.