Provided is a program storage device and a program storage system for transferring an appropriate program in advance to a numerical controller. A program storage device that transfers a program or page to a numerical controller includes: a statistical information collection unit that records at least a total number of times of transfer of the program or page transferred to the numerical controller; a prediction unit that predicts the program or page to be transferred subsequently, based on an execution state of the program in the numerical controller and the total number of times of transfer;and a program transfer control unit that transfers the predicted program or page.