An evaporator comprises tubes, configured for coolant flow, stacked in regularly spaced relation to one another, each of the tubes formed by coupled tube plates. Also comprising a tank in fluid communication with the tubes at an upper or lower side; inlet and outlet end-plates which respectively have an inflow part and an outflow part at an upstream side of coolant flow and positioned at respective end sides of the stacked tubes; and inlet and outlet manifolds in fluid communication with the tank and coupled to the inflow and outflow parts to define a coolant flow passage. The outlet manifold has a coolant movement preventing part isolating a rear portion from the coolant flow passage and comprises a closed space formed by joining the outlet end-plate and the outlet manifold to prevent formation of a dead zone where the coolant from the tank flows into a downstream side of the outlet manifold and is whirled therein.