PROBLEM TO BE SOLVED: To improve water draining, water management, well draining on a paddy field surface, activation of microbes breeding, and growth of a deep part of a root of paddy rice, which can be attained in a manner that, because a lower part of a plow member scoops field soil to be discharged to a lateral side and forms a digging groove at a vertical port passage formation position while a travel machine body travels, a distance from a field ground surface to a core soil layer is reduced, and thereby water draining performance and air permeability in the field is favorably maintained.SOLUTION: The field vertical port passage formation device includes: a machine frame 4 arranged on an attachment frame 3 with a pivotal attachment mechanism 5 so as to be freely rotated horizontally an oscillation mechanism 7 for oscillatingly operating a penetration beam 6 an expansion member 19 arranged on the machine frame, expanding a side face of a penetration mark groove S formed by the penetration beam and extended vertically in field soil W, and capable of forming a vertical port passage T opened on a ground surface M an expansion mechanism 20 for forcibly expansion-operating the expansion member and a plow member 28 arranged on the machine frame, for scooping the field soil to be discharged to a lateral side, and thereby capable of forming a digging groove U at a vertical port passage formation position D.SELECTED DRAWING: Figure 16
