Abstract: An additive manufacturing system includes an additive manufacturing unit configured to shape an object including a plurality of layers, a measurement unit configured to measure a state of each of the plurality of layers, and a control unit. The control unit includes a storage unit configured to store reference information based on internal defect information indicating a defect existing inside a sample object shaped by the additive manufacturing unit and including the plurality of layers, based on an electromagnetic wave which has passed through the sample object, and sample measurement information indicating a measurement result of the plurality of layers of the sample object measured by the measurement unit, and an estimation unit configured to estimate whether a defect occurs inside the object, based on measurement information indicating a measurement result of the plurality of layers of the object measured by the measurement unit and the reference information.