An inspection method is provided to inspect whether abnormality such as omission, chip, abnormal size, abnormal shape, and contamination exists or not in a content that is covered with a packaging material, especially an opaque packaging material. Further, an inspection method of a content in a packaging container is provided with which inspection of a content can be performed rapidly, accurate inspection is possible for any combination of a content and a packaging material, there is no adverse effect on a content such as a pharmaceutical agent or food, no reputational damage is caused, and an inspection apparatus can be installed easily in existing manufacturing equipment. These are performed by an inspection method in which inspection to detect abnormality in the content is performed employing either a difference in increasing speed of temperature or a difference in decreasing speed of temperature of the packaging container.
