1. A process time estimating apparatus for estimating the process time for manufacturing an object comprising a process time estimating section, a process occupancy time measurement section and a process program scheduling section, wherein said process time estimating section comprises: a neural network device for estimating process times for individual machining operations to be performed in a planned process for manufacturing the object; an estimation input factor extracting section for extracting estimation input factors including drawing information and manufacturing equipment identification for each machining operation to be performed on the object from process planning data associated with said object; a storage section for storing input factors obtained from said estimation input factor extracting section and for transmitting said input factors to said neural network device for neural network learning; and a selecting section for selecting an actual time measurement for individual machining operations to be applied to said neural network device for neural network learning, wherein said process occupancy time measurement section reads a process code for each machining operation process and automatically makes an actual time measurement for the process corresponding to said process code wherein said selecting section makes its selection by determining if the actual time measurement is within a predetermined range of the process time estimated by the neural network device, and wherein said process program scheduling section receives output information from the process occupancy time measurement section, stores an estimated process time outputted from the neural network device, outputs estimation time data for each machining operation to said selecting section and outputs an updated estimate of the process time for manufacturing the object.