A machine learning method for learning a predicted life of a NAND flash memory provided in a numerical control device for a machine tool, the method comprising the steps of:
- observing a state variable obtained based on at least one of a rewrite count, a rewrite interval, a read count, a temperature in a use environment, an error rate, information concerning a manufacturer, and information concerning a manufacturing lot for the NAND flash memory, and information concerning an error correction coding performance, information concerning a manufacturer, and information concerning a manufacturing lot for a memory controller which performs error correction coding processing for the NAND flash memory;
- and
- learning the predicted life of the NAND flash memory based on teacher data, and training data generated from the state variable and data associated with a life of the NAND flash memory.