An experimental study on the improvement of aerodynamic characteristics of an arrow wing by lateral blowing in low and high speed flows, has been conducted. An arrow wing [1,2], which is one of the baseline configurations of next-generation SST, is selected for the experiments. As compared to the delta wing, it is known that an arrow wing has higher the ratio of lift to drag and improvement of stability in low speed region because of the supersonic leading edge. However, for better and cost effective configurations higher L/D is requested for the development of SST. The testing model is the combination of a body of a circular cylinder and conical apex and a modified arrow wing with aspect ratio of 1.91. The lateral blowing is realized by injecting a pair of steady jets in a direction parallel to the trailing edge of the wing. The experiments have been performed in the transonic and supersonic wind tunnel located at ISAS under the testing conditions of M∞(free-stream Mach number) of 0.3 ~2.3, Re unit (unit Reynolds number) of 1.06×107~3.10× 107 [1/m], angle of attack of -15°~30° and Cj (jet momentum coefficient) of 0.0084 ~0.0316. The results show that the CL and L/D is increased by lateral blowing while CD is slightly increased for positiveangle of attack. The results suggest that the lateral blowing can be useful for the improvement of aerodynamic characteristics of the arrow wing in low and high speed flows.