This study aims at elucidating the functions required of pocket-type rockfall protection structures, and also at establishing atechnique to verify the performance of such structures. Falling-weight impact tests on the diamond-shaped wire net used for rockfall protection structures were performed for analyzing the behavior of conventional pocket-type rockfall protection nets with the aim of calculating the amount of energy absorbed by diamond-shaped wire net as well as of identifying a constitutive law for materials that was applicable to numerical analysis of energy absorption.