A power transmission system comprising: a power transmitting unit having a power transmitting coil (Lp); and a power receiving unit having a power receiving coil (Ls), wherein the power transmitting unit includes: power transmitting unit-side resonance capacitors (Cr, Cp) that configure a power transmitting unit-side resonance circuit along with the power transmitting coil (Lp), wherein a first resonance capacitor (Cp) is provided in parallel with respect to the power transmitting coil (Lp) and wherein a second resonance capacitor (Cr) is connected in series with the first resonance capacitor (Cp) and the power transmitting coil (Lp); and a power transmitting unit-side alternating current generation circuit that is electrically connected with the power transmitting coil (Lp), including a switching circuit configured of a parallel connection circuit in which a switching element, a diode, and a capacitor are connected in parallel, and an inductor (Lf), wherein one terminal of the switching element, of the diode and of the capacitor is respectively connected to a ground potential terminal of a direct current voltage source, wherein another terminal of the switching element, of the diode and of the capacitor is respectively connected to one terminal of the inductor, wherein the other terminal of the inductor is connected to another terminal of the direct current voltage source, wherein a value of inductance of the inductor (Lf) is larger than a value of inductance of the power transmitting coil (Lp), and wherein an impedance value of the inductor (Lf) is high at a switching frequency of the switching frequency of the switching element, thus the inductor forming a direct current source, the power receiving unit includes: a power receiving unit-side resonance capacitor (Cs, Crs) that configures a power receiving unit-side resonance circuit along with the power receiving coil (Ls); and a power receiving unit-side rectification circuit that is connected with the power receiving coil and rectifies an alternating current generated on the power receiving coil, wherein a part of the power transmitting unit-side resonance circuit and a part of the power receiving unit-side resonance circuit constitutes an electromagnetic field resonance coupling circuit in which the power transmitting unit-side resonance circuit and the power receiving unit-side resonance circuit resonate with each other to transmit power from the power transmitting unit to the power receiving unit. a power transmitting unit having a power transmitting coil (Lp); and a power receiving unit having a power receiving coil (Ls), wherein the power transmitting unit includes: power transmitting unit-side resonance capacitors (Cr, Cp) that configure a power transmitting unit-side resonance circuit along with the power transmitting coil (Lp), wherein a first resonance capacitor (Cp) is provided in parallel with respect to the power transmitting coil (Lp) and wherein a second resonance capacitor (Cr) is connected in series with the first resonance capacitor (Cp) and the power transmitting coil (Lp); and a power transmitting unit-side alternating current generation circuit that is electrically connected with the power transmitting coil (Lp), including a switching circuit configured of a parallel connection circuit in which a switching element, a diode, and a capacitor are connected in parallel, and an inductor (Lf), wherein one terminal of the switching element, of the diode and of the capacitor is respectively connected to a ground potential terminal of a direct current voltage source, wherein another terminal of the switching element, of the diode and of the capacitor is respectively connected to one terminal of the inductor, wherein the other terminal of the inductor is connected to another terminal of the direct current voltage source, wherein a value of inductance of the inductor (Lf) is larger than a value of inductance of the power transmitting coil (Lp), and wherein an impedance value of the inductor (Lf) is high at a switching frequency of the switching frequency of the switching element, thus the inductor forming a direct current source, the power receiving unit includes: a power receiving unit-side resonance capacitor (Cs, Crs) that configures a power receiving unit-side resonance circuit along with the power receiving coil (Ls); and a power receiving unit-side rectification circuit that is connected with the power receiving coil and rectifies an alternating current generated on the power receiving coil, wherein a part of the power transmitting unit-side resonance circuit and a part of the power receiving unit-side resonance circuit constitutes an electromagnetic field resonance coupling circuit in which the power transmitting unit-side resonance circuit and the power receiving unit-side resonance circuit resonate with each other to transmit power from the power transmitting unit to the power receiving unit.