A non-contact power supply system comprising: a power transmission device including a power transmission-side resonant circuit; and a power reception device including a power reception-side resonant circuit, wherein the non-contact power supply system is configured to transmit electric power by a magnetic field resonance method from the power transmission device to the power reception device, wherein the power transmission device includes: a load detection circuit arranged to detect a magnitude of a load in the power transmission; and a control circuit arranged to perform power transmission control based on a detection result of the load detection circuit, wherein the power reception device includes: a load circuit; a power reception circuit arranged to output, toward the load circuit, electric power based on received electric power received by the power reception-side resonant circuit; and a suppressor circuit interposed between the power reception circuit and the load circuit, and wherein the suppressor circuit is arranged to operate such that the output power of the power reception circuit is maintained constant even though power consumption of the load circuit varies, wherein the suppressor circuit comprises a constant-resistance circuit configured to output a constant current proportional to the input voltage of the suppressor circuit, characterized in that the constant-resistance circuit comprises two transistors (411, 412) forming a current mirror circuit; and the suppressor circuit further comprises a transistor configured to consume a decrement in power resulting from a decrease in power consumption of the load circuit. a power transmission device including a power transmission-side resonant circuit; and a power reception device including a power reception-side resonant circuit, wherein the non-contact power supply system is configured to transmit electric power by a magnetic field resonance method from the power transmission device to the power reception device, wherein the power transmission device includes: a load detection circuit arranged to detect a magnitude of a load in the power transmission; and a control circuit arranged to perform power transmission control based on a detection result of the load detection circuit, wherein the power reception device includes: a load circuit; a power reception circuit arranged to output, toward the load circuit, electric power based on received electric power received by the power reception-side resonant circuit; and a suppressor circuit interposed between the power reception circuit and the load circuit, and wherein the suppressor circuit is arranged to operate such that the output power of the power reception circuit is maintained constant even though power consumption of the load circuit varies, wherein the suppressor circuit comprises a constant-resistance circuit configured to output a constant current proportional to the input voltage of the suppressor circuit, the power transmission device includes: a load detection circuit arranged to detect a magnitude of a load in the power transmission; and a control circuit arranged to perform power transmission control based on a detection result of the load detection circuit, wherein a load detection circuit arranged to detect a magnitude of a load in the power transmission; and a control circuit arranged to perform power transmission control based on a detection result of the load detection circuit, wherein the power reception device includes: a load circuit; a power reception circuit arranged to output, toward the load circuit, electric power based on received electric power received by the power reception-side resonant circuit; and a suppressor circuit interposed between the power reception circuit and the load circuit, and wherein a load circuit; a power reception circuit arranged to output, toward the load circuit, electric power based on received electric power received by the power reception-side resonant circuit; and a suppressor circuit interposed between the power reception circuit and the load circuit, and wherein the suppressor circuit is arranged to operate such that the output power of the power reception circuit is maintained constant even though power consumption of the load circuit varies, wherein the suppressor circuit comprises a constant-resistance circuit configured to output a constant current proportional to the input voltage of the suppressor circuit, characterized in that the constant-resistance circuit comprises two transistors (411, 412) forming a current mirror circuit; and the suppressor circuit further comprises a transistor configured to consume a decrement in power resulting from a decrease in power consumption of the load circuit.