To investigate an evaluation method of collapse mechanisms and the safety limit of RC buildings, a shake-table test of a 1/4 scale model of a 4story RC structure with shear walls was carried out. The specimen was designed to exhibit a frame-sway mechanism in both directions. In the test, the first-floor wall failed in flexure in the X-direction as designed; however, the first-floor wall in the Y-direction failed in shear, which did not match the design. Moreover, collapse mechanism and safety limit of the whole frame was discussed comparing the analytical result with the test result.