A power supply control apparatus for an electric vehicle, the power supply control apparatus comprising: a power supply; a main circuit connecting the power supply to an electric load to be driven by the power supply and including a smoothing capacitor in parallel with the electric load to smooth a fluctuation in the input voltage to the electric load; first and second main contactors (17, 18) interposed between the power supply and the electric load, the first main contactor being connected to a cathode of the power supply, the second main contactor being connected to an anode of the power supply; a precharge circuit connected in parallel with the first main contactor and including a precharge contactor and a resistance element; precharge control means for turning on the second main contactor and the precharge contactor during a precharging phase, while the first main contactor is off, to precharge the smoothing capacitor; voltage detection means for detecting, as a capacitor voltage, the voltage of the smoothing capacitor during the precharging phase; current detection means for detecting, as a precharge current (Ipre), a current flowing through the main circuit during the precharging phase; precharge completion determination means for determining, during the precharging phase, completion of the precharging if the capacitor voltage is equal to or greater than a predetermined value; timeout determination means for determining that a timeout occurs when an elapsed time (t) from start of the precharging phase reaches a predetermined timeout time (Tout) without completion of the precharging, the power supply control apparatus being characterized by further comprising retry permission means for subsequently granting the precharge control means permission to retry the precharging under a condition that when the timeout occurs the precharge current is within a permission region predefined by a predetermined current range between 0 A and a predetermined threshold current and a period from the start of the precharging phase until a predetermined period elapses into the precharing phase, the predetermined period being equal to or shorter than the timeout time. a power supply; a main circuit connecting the power supply to an electric load to be driven by the power supply and including a smoothing capacitor in parallel with the electric load to smooth a fluctuation in the input voltage to the electric load; first and second main contactors (17, 18) interposed between the power supply and the electric load, the first main contactor being connected to a cathode of the power supply, the second main contactor being connected to an anode of the power supply; a precharge circuit connected in parallel with the first main contactor and including a precharge contactor and a resistance element; precharge control means for turning on the second main contactor and the precharge contactor during a precharging phase, while the first main contactor is off, to precharge the smoothing capacitor; voltage detection means for detecting, as a capacitor voltage, the voltage of the smoothing capacitor during the precharging phase; current detection means for detecting, as a precharge current (Ipre), a current flowing through the main circuit during the precharging phase; precharge completion determination means for determining, during the precharging phase, completion of the precharging if the capacitor voltage is equal to or greater than a predetermined value; timeout determination means for determining that a timeout occurs when an elapsed time (t) from start of the precharging phase reaches a predetermined timeout time (Tout) without completion of the precharging, the power supply control apparatus being characterized by further comprising retry permission means for subsequently granting the precharge control means permission to retry the precharging under a condition that when the timeout occurs the precharge current is within a permission region predefined by a predetermined current range between 0 A and a predetermined threshold current and a period from the start of the precharging phase until a predetermined period elapses into the precharing phase, the predetermined period being equal to or shorter than the timeout time.