An electric power transmission system may include: a power transmission antenna that constitutes a series resonator with an inductance component of L1 and a capacitance component of C1, and to which AC power is input; a power receiving antenna that constitutes a series resonator with an inductance component of L2 and a capacitance component of C2, and which receives electromagnetic energy from the power transmission antenna via electromagnetic fields; a rectifying unit that rectifies an output of the power receiving antenna to output DC power; and a load to which an output of the rectifying unit is input, wherein, when a coupling coefficient between the power transmission antenna and the power receiving antenna is k, if load resistance value R is used in a range that satisfies Rmin≦R≦Rmax, the following relationships are established: L 1 ⁢ C 1 = L 2 ⁢ C 2 ⁢ ⁢ and ( 2 ) L 1 C 1 > L 2 C 2 ⁢ ⁢ and ( 6 ) R m ⁢ ⁢ i ⁢ ⁢ n ≤ k ⁢ L 2 C 2 ≤ R m ⁢ ⁢ ax . ( 8 )