Heat treatment apparatus, abnormality detection method in heat treatment and computer readable memory medium capable of accurately detecting abnormality in the heat treatment of a substrate

The invention aims to accurately detect abnormality in the heat treatment of a substrate. A heat treatment apparatus for performing heat treatment on a wafer includes: a heat plate (132) for carrying a wafer (W) and heating the same; a plurality of wafer support members (170) arranged to project higher upward than the carrying surface (132a) of the heat plate (132); a weight sensor (184) for detecting a load that changes along with the carrying state of the wafer (W) supported by the wafer support members (170); and a control part (300) for determining that the carrying state of the wafer supported by the wafer support members (170) is abnormal when the load detected by the weight sensor (184) is smaller than a predetermined threshold value.