PURPOSE: To prevent a tube wall from being locally damaged by static electricity and to obtain an economical fluororesin tube heat exchanger by forming an active layer from which a fluorine atom is eliminated on the circumferential surface of at least one of fluororesin tubes in the fluororesin tube heat exchanger whose heat transfer tubes consist of fluororesin tubes.

CONSTITUTION: When the surface of a fluororesin tube 2 is treated with a surface treating agent, a fluorine atom in the fluororesin is eliminated from the resin as an alkali fluoride by the reaction and the surface of the resin is activated, so that an active layer 3 having small electric resistance is formed on the surface thereof. The thickness of this active layer 3 can be controlled by a kind of alkali metal, treating time, treating temperature, etc. Further, since the volume resistivity of the active layer 3 has the electric conductivity of 105W1010Ω.cm or so, static electricity, even if it is generated, is dispersed over the entire surface of the active layer 3 on the tube surface, and consequently the local concentration of electric charges is prevented to make no pin hole or the like in the tube wall. Thus, the tube wall is protected from being locally damaged, and a long-life fluororesin tube heat exchanger can be obtained.