A heat exchanger comprises a first plate and a second plate. A coolant flow passage is formed by brazing the first plate and the second plate by use of a first brazing filler metal. A pipe is brazed between a first groove portion provided in the first plate and a second groove portion provided in the second plate by use of a second brazing filler metal. A pair of first flanges provided contiguously with the first groove portion. Each of the first flanges includes an inner surface. A pair of second flanges provided contiguously with the second groove portion. Each of the second flanges includes an inner surface. At least one of the inner surfaces of the first flanges and the inner surfaces of the second flanges is covered with the second brazing filler metal. The first and second flanges are held by jigs upon brazing of the pipe.