This paper reports the results of evaluation on out-of-plane vibration characteristics for unreinforcement walls of historic masonry constructions based on microtremor measurement, eigenmode analysis and proposal of estimation formula of natiral frequency. Major findings from the research are as follows: (1) In the microtremor measurement, vibration characteristics are clarified: 1st natural frequency of walls had large aspect ratio are small, and damping factors are between 1 and 4%. (2) In the eigenmode analysis based on microtremor measurement, it is found out how masonry constructions vibrate. (3) Applying the proposed simple estimation formula, the range of 1st natiral frequency can be found.
