Provided are a heat exchanger and a heat exchange system which have satisfactory heat exchange efficiency, enable a fluid passage to be cleaned and sterilize easily, and enable the conditions thereof to be confirmed easily.A heat exchanger is provided with a first flow passage-forming member (11, 13) having a container shape and a flow passage-forming second member (12) disposed on the inside of the first flow passage forming member (11, 13) so that the flow passage-forming second member (12) is mountable and dismountable from the first flow passage-forming member (11, 13). The first flow passage-forming member (11, 13) of the heat exchanger (1) is configured in such a manner that: the diameter of the inner peripheral surface of the peripheral wall section of the container shape gradually decreases from the upper part toward the lower part a first flow passage (134) through which heat exchange liquid flows is formed inside the peripheral wall section and a helical second flow passage (114) through which liquid to be subjected to heat exchange flows is formed between the inner peripheral surface of the first flow passage-forming member (11, 13) and the outer peripheral surface of the flow passage-forming second member (12).La présente invention concerne un échangeur de chaleur et un système déchange de chaleur qui présentent une efficacité déchange de chaleur satisfaisante, permettent de nettoyer un passage de fluide, se stérilisent facilement et permettent aux conditions de celui-ci dêtre facilement confirmées. Un échangeur de chaleur est doté dun premier élément (11, 13) de formation de passage découlement ayant la forme dun récipient et dun second élément (12) de formation de passage découlement disposé sur lintérieur du premier élément (11, 13) de formation de passage découlement afin que le second élément (12) de formation de passage découlement puisse être monté et démonté à partir du premier élément (11, 13) de formation de passage découlement. Le premier élé
