The aerodynamic derivatives of a biconvex-flat airfoil (thickness ratio of 10 per cent), and double-wedge airfoils (thickness ratios of 10, 15, 20 percent), performing pitching oscillation in supersonic flow at the range of Mach number2-3, were measured and compared with the linearized theory, piston theory and Van Dyke's nonlinear theory which includes the effect of the airfoil thickness. The tested reduced frequency range was 0.01-0.05 and the Reynolds numver range was 2.8 by 10(6)-3.6 by10(6) based on the chord length. In spite of the existence of the detached shock wave in front of the leading edge of the biconvex-flat airfoil, all experimental results agree quite well with the nonlinear theory. Schlieren photographs were taken in order to observe the flow field around the airfoils