A tube used in a heat exchanger, wherein a tube body includes a curved end portion, a pair of parallel portions, a pair of inclination portions, and a fixed portion in which a long end part extending from one of the pair of inclination portions is bent to hold therebetween a short end part extending from the other of the pair of inclination portions, and the tube is a pipe member having a flattened shape in cross-section. Poor brazing is reduced by making the inclination angle of at least part of the other inclination portion with respect to the flat plate portion larger than that of the one inclination portion.