Floor impact noise in apartment houses is a noise source that needs to be reduced first among the noise generated in residential spaces. Among the floor impact sound reduction methods, a plan that a downstairs resident can apply to his or her house is to improve the ceiling structure. In order to improve the performance of the floor impact sound isolation of the ceiling, a vibration-isolation hanger, sound-absorbing material and sound-insulating material were applied. In this study, a structure that effectively reduces the main frequency of floor impact sound is periodically arranged in the ceiling of an apartment building, and an acoustic metamaterial made of lightweight material is applied and compared in laboratory conditions. The light-weight impact sound and the rubber ball impact sound were measured and compared, and it was confirmed that the floor impact sound was reduced when the acoustic metamaterial was applied inside the ceiling.