PURPOSE: To both decrease resistance of fluid and promote radiation and absorption of heat, by using a stainless steel web in which stainless steel wool of uniform wire size is collected.

CONSTITUTION: A cylindrical inner frame 21 and a cylindrical outer frame 22 made of stainless steel are concentrically arranged on a base plate 24, and a web 23a made of stainless steel is filled in an annular space. The web is made of stainless steel wool in wire size of 100μm or less, and 25μm or less especially when a quick response is required for absorption and radiation of heat. Next, using a press member 25 at 1,000W1,200°C in a vacuum, the web 23a is pressed so as to obtain desired density and simultaneously sintered (hot press). A heat exchanger 18, equipped with a sintered unit 23 of stainless steel web in desired density and height acquired in such way, cylindrical inner frame 21 and the cylindrical outer frame 22, is obtained.