Fan and water heater provided with the same, and impeller and water heater provided with the same

An impeller comprising:

• a first member including a shroud formed in an annular shape and a first blade that is formed so as to extend from an inner circumferential side to an outer circumferential side of a first back surface of said shroud and protrude from said first back surface;
• and
• a second member including a main plate formed in a disc shape and a second blade that is formed so as to extend from an inner circumferential side to an outer circumferential side of a second back surface of said main plate and protrude from said second back surface,
• said first member and said second member being integrally molded by a resin containing a fibrous filler,
• said first member and said second member being coupled by welding said first blade and a second front surface on a side opposite to said second back surface,
• at least one of said second front surface and a first front surface on a side opposite to said first back surface including an inner circumferential side gate mark portion located on a circumference on the inner circumferential side and an outer circumferential side gate mark portion located on a circumference close to the outer circumferential side relative to said inner circumferential side gate mark portion.