PURPOSE: To improve a heat exchanging efficiency without engaging with fiber sludge in a spiral type heat exchanger using fluid containing fibrous material.

CONSTITUTION: A spiral type heat exchanger formed by winding a heat transfer plate 1 comprises stud pins 2 as spacers at a one-way channel 3, and disturbance bars 5 at the other channel 4. The bars 5 are intermittently arranged in a zigzag manner, and mounted at an angle to extend in an advancing direction of fluid. Accordingly, since the intermittent bars 5 are arranged in the zigzag manner, the fluid is dispersed and mixed to improve heat transfer performance. Since the fluid has an angle for extending in its advancing direction, it has the same effect as extension of an width of the bars supported between the plates 1 to provide a strong holding effect and to improve a heat exchanging efficiency by a turbulent flow effect of the fluid.