The aerodynamic force acting on the flapping wing of insect like three-axis flapping robot "MOTH-1" was measured while it was moving in a hovering mode. Two flapping modes were used; one is the 1^<st> Fourier approximation of actual hovering motion and the other is its 3^<rd> Fourier approximation. Measured aerodynamic force of 3^<rd> Fourier approximation was larger than that of 1^<st> one, indicating the higher order oscillation in the 3^<rd> Fourier approximation exerted additional force on the wing. Thus, the higher order oscillation in the motion, especially in the feathering motion, may act as the enhancer of aerodynamic force by manipulating the angle of attack of flapping wing.