A control device which predicts the timing of disconnection of a power supply is provided with a machine learning device configured to learn the disconnection timing of the power supply. The machine learning device is provided with a state observation unit configured to observe an operation content for the control device for each user as one of state variables representative of a present state of an environment, a determination data acquisition unit configured to acquire determination data which indicates that power disconnection of the control device is commanded by the user, and a learning unit configured to learn the operation content for each user and a command for the power disconnection in association with each other by using the state variable and the determination data.