In this study, significant sound-absorbing properties of a fine, lightweight particle powder, different from the regular particle powder. Sound absorbing properties are generally not obtained for a thin powder layer with a thickness of only several millimeters. Therefore, we measured the normal incident sound absorption coefficient using an acoustic tube in this study. The results indicated the differences in the sound absorbing properties because of varying particle sizes and bulk densities. The fine, lightweight particle powder showed a decrease in the apparent speed of sound, which is not seen in normal granules. In addition, a high sound absorption performance in a low-frequency range can be obtained using a thin layer of such particles.