Impact detecting apparatus and packaging system

An impact detection sensor is attached to a packaging container. When the packaging container is subjected to impacts downward in a vertical direction twice, i.e., a bottom surface of the packaging container is subjected to impacts twice, a weight moves downward in the vertical direction by the application of the first impact, and is seen through a weight indicator unit located on the bottom of an impact detection sensor. At the time of the application of the second impact, the weight moved downward in the vertical direction is prevented from moving back to. an initial position by a pressing portion, and seen through the same bottom weight indicator unit.