METHOD AND DEVICE FOR TESTING SEALED VESSEL

PROBLEM TO BE SOLVED: To precisely determine quality of a closed state even when a sensor output value of a non-defective vessel changes because of presence of an adjacent defective vessel.SOLUTION: This sealed vessel tester includes: a measuring means 23 for measuring a distance with a lid part at a center part in the lid part and two points away at a given distance from this center part of the lid part of a cup-type vessel encased in a carton case; and a determining means 27 for computing a difference between a mean value of positions of the two points and a position of the center part as a determination value to determine that the cup-type vessel is a defective product if this determination value deviates from a given range. A distance between one of the two points and the center part is an extraction point distance, and the extraction point distance is a distance set so that the determination value computed in the non-defective cup-type vessel may indicate a value not deviating from the given range when the non-defective cup-type vessel and the defective cup-type vessel are disposed adjacent to each other.