Problem to be SolvedA plate laminate type heat exchanger having high heat exchange efficiency is provided.SolutionIn a plate laminate type heat exchanger 100, both ends of a protrusion 10 converge into an inlet port for high temperature fluid 58a and an outlet port for high temperature fluid 58b. A pair of core plates 53 and 54 is assembled in such a way that the side of the core plate 53 on which the protrusion 10 is not formed faces the side of the core plate 54 on which the protrusion 10 is not formed and the protrusions 10 and 10 formed on the respective core plates are paired but oriented in opposite directions. The pair of core plates 53 and 54 form a plurality of tubes surrounded by the walls of the protrusions 10 and 10, and the tubes form high temperature fluid compartments.