Abstract: A technique for estimating a process condition without limiting forms (such as shapes) of an object is presented, and a process condition estimating apparatus for estimating a process condition in which an object is processed, and which includes an input unit configured to input measurement data acquired at a predetermined position of the object; and an estimation unit configured to estimate the process condition from the measurement data, based on a process-condition-estimating function for inputting the measurement data and outputting an estimation value of the process condition.