An embodiment vehicle headrest device includes a headrest including a pad portion configured to contact and support a sitting passenger's head and a cover portion positioned behind the pad portion, the pad portion being configured to move diagonally, a main frame coupled to a headrest stay and configured to move upwards/downwards along the headrest stay, and a motor module portion connected to the pad portion and the main frame such that, in operation, the motor module portion is configured to move an entirety of the headrest, including the main frame, upwards/downwards or to move only the pad portion diagonally.