A voltage regulator includes: a drive voltage generating part for generating a drive voltage and then apply the drive voltage to a drive line; an output transistor for outputting a voltage corresponding to a voltage value of the drive line as the internal source voltage; and a compulsory drive circuit including a capacitor element configured to receive the source voltage at one end, a first switching element for receiving a ground voltage and applying the ground voltage to the other end of the capacitor element by being set in an ON state over a period in which the selected operational mode is the standby mode, and a second switching element that connects the other end of the capacitor element to the drive line only for a predetermined period in an ON state when the operational mode transitions from the standby mode to the active mode.