A scrape-off type heat exchanger, the scrape-off type heat exchanger passing a heating/cooling medium in between a tubular jacket and a heat transfer tube, the heat transfer tube being extended in the inside of the jacket, and the scrape-off type heat exchanger passing a process fluid through the inside of said heat transfer tube to perform heat exchange between the process fluid and the heating/cooling medium, while scraping off the process fluid attached to an inner wall of said heat transfer tube, comprising: a suction delivery element, the suction delivery element being closely contacted with the inner wall of said heat transfer tube, and making a reciprocating motion in the inside of said heat transfer tube, while being rotated, to suck the process fluid into said heat transfer tube and deliver the process fluid from said heat transfer tube, while scraping off the process fluid, said heat transfer tube being a corrugated pipe, having an inner wall with a helical part, the helical part providing a female thread-like spiral geometry, being formed by alternately connecting an arcuate ridge and an arcuate root to each other, with said suction delivery element, both end parts, thereof being closely contacted and screwed with the helical part of said heat transfer tube, a scraping part for scraping off the process fluid attached to the inner wall of said heat transfer tube being provided in between said both end parts,, and check valves (310, 320) being disposed in said both end parts,, thereby the process fluid sucked into the inside of said heat transfer tube flowing into the inside of said suction delivery element from one end part, and flowing out from another end part into the inside of said heat transfer tube, the process fluid, having flown out into the inside of said heat transfer tube, being forced out to the outside of said heat transfer tube by said another end part with a reciprocating motion of said suction delivery element being made. a suction delivery element, the suction delivery element being closely contacted with the inner wall of said heat transfer tube, and making a reciprocating motion in the inside of said heat transfer tube, while being rotated, to suck the process fluid into said heat transfer tube and deliver the process fluid from said heat transfer tube, while scraping off the process fluid, said heat transfer tube being a corrugated pipe, having an inner wall with a helical part, the helical part providing a female thread-like spiral geometry, being formed by alternately connecting an arcuate ridge and an arcuate root to each other, with said suction delivery element, both end parts, thereof being closely contacted and screwed with the helical part of said heat transfer tube, a scraping part for scraping off the process fluid attached to the inner wall of said heat transfer tube being provided in between said both end parts,, and check valves (310, 320) being disposed in said both end parts,, thereby the process fluid sucked into the inside of said heat transfer tube flowing into the inside of said suction delivery element from one end part, and flowing out from another end part into the inside of said heat transfer tube, the process fluid, having flown out into the inside of said heat transfer tube, being forced out to the outside of said heat transfer tube by said another end part with a reciprocating motion of said suction delivery element being made.