To provide a voltage converter capable of correctly determining the generation of a leak current and a driving system equipped with the same, in a semiconductor switching element for controlling precharge of a capacitor provided on an input side of a driving circuit.

In a DC-DC converter 30, an MOS transistor 35 and a resistor 36 are connected in series, and connected to a negative bus bar 14 in parallel to a system main relay SMR2. An ECU 40 determines whether or not a leak current is generated in the MOS transistor 35 on the basis of a current Ir flowing through the resistor 36 detected using a current sensor 38. The ECU 40 varies a reference current used for determining whether or not the leak current has been generated on the basis of the degree of dew condensation of the DC-DC converter 30 detected by a dew condensation sensor 39. When the MOS transistor 35 determines that the leak current has not been generated, the ECU 40 precharges a capacitor 22.