Albedo was measured in a hinoki forest with a density of 20,000 stems ha-1. With some variation, albedo ranged from 0.14 to 0.17 (average 0.157) in winter and from 0.18 to 0.21 (average 0.195) in summer. These values are larger than values reported previous studies for Hinoki forests and as large as the albedo for grasslands. This cause was thought that incident radiation is reflected by the upper canopy surface and returned to the atmosphere easily. This process was verified by the vertical distribution of incident and reflected radiation. Around 60% of the incident radiation was absorbed, and most of the reflected radiation was emitted in the upper 1m of the canopy layer.