Abstract: A stack type evaporator according to the invention comprises a plurality of plate-shaped tubular elements stacked in a direction of their width with a fin member interposed between two of such tubular elements which have inlet header portions at their ends and outlet header portions at their further ends so that coolant can flow straight within said tubular elements, a pair of dish-shaped core plates which constitute each tubular element having inner surfaces provided with ribs arranged at regular intervals in a direction of coolant flow, wherein an end surface of each rib protruding from one core plate is alternately bonded to a flat body of the other core plate whereby the coolant paths within each tubular element are formed parallel with each other and straight from the inlet header portion toward the outlet header portion.