A relay drive apparatus (100, 600) that controls supply of electric power to an electronic device, the relay drive apparatus (100, 600) comprising: a relay switch that includes a coil and that is turned ON when a voltage of the coil is equal to or greater than a predetermined value to supply the electric power to the electronic device, the coil having one end to which a predetermined voltage is applied and having another end grounded via a resistor; and a voltage adjusting section (101, 105, 106, 601) that increases the voltage of the coil to a value equal to or greater than the predetermined value by drawing a current which flows through the coil and allowing the current to flow to a ground not via the resistor when the supply of the electric power starts and that reduces the voltage of the coil to a voltage not below the predetermined value by gradually reducing a drawing amount of the current which flows through the coil after the supply of the electric power starts, characterised in that the voltage adjusting section (101, 105, 106, 601) includes: a control section (101, 601) that outputs a control signal when the supply of the electric power starts, and that stops outputting the control signal after a predetermined time passes from the start of the output of the control signal; a time constant circuit that causes a transient change in the control signal when the control section (101, 601) stops outputting the control signal; and a transistor that conducts when receiving the control signal and draws the current flowing through the coil and gradually reduces the drawing amount by receiving the control signal in which the transient change is caused by the time constant circuit after the outputting of the control signal stops. a relay switch that includes a coil and that is turned ON when a voltage of the coil is equal to or greater than a predetermined value to supply the electric power to the electronic device, the coil having one end to which a predetermined voltage is applied and having another end grounded via a resistor; and a voltage adjusting section (101, 105, 106, 601) that increases the voltage of the coil to a value equal to or greater than the predetermined value by drawing a current which flows through the coil and allowing the current to flow to a ground not via the resistor when the supply of the electric power starts and that reduces the voltage of the coil to a voltage not below the predetermined value by gradually reducing a drawing amount of the current which flows through the coil after the supply of the electric power starts, characterised in that the voltage adjusting section (101, 105, 106, 601) includes: a control section (101, 601) that outputs a control signal when the supply of the electric power starts, and that stops outputting the control signal after a predetermined time passes from the start of the output of the control signal; a time constant circuit that causes a transient change in the control signal when the control section (101, 601) stops outputting the control signal; and a transistor that conducts when receiving the control signal and draws the current flowing through the coil and gradually reduces the drawing amount by receiving the control signal in which the transient change is caused by the time constant circuit after the outputting of the control signal stops. a control section (101, 601) that outputs a control signal when the supply of the electric power starts, and that stops outputting the control signal after a predetermined time passes from the start of the output of the control signal; a time constant circuit that causes a transient change in the control signal when the control section (101, 601) stops outputting the control signal; and a transistor that conducts when receiving the control signal and draws the current flowing through the coil and gradually reduces the drawing amount by receiving the control signal in which the transient change is caused by the time constant circuit after the outputting of the control signal stops.