disclosed is an automatically openable and closable hopper set for a fruit weighing and sorting machine , wherein a hopper having two lower scale plates and a pivotally connected door is used to carry a fruit to be sorted by weight . the door is normally retained to a closed position by means of a hook portion of an arm member disposed at one side of the hopper . when the carried fruit is heavier than a set value of a weighing device passed by the hopper set , the scale plates of the hopper depress a scale rod of the weighing device , causing the hopper to descend and tilt , which further causes the arm member to shift and the hook portion to release the door from the hopper , permitting the fruit to immediately fall out of the hopper and into a collection box .