Component analysis of a novel white-colored truffle native to Japan, Tuber japonicum, was performed to determine its characteristic features. The analysis of odor-active volatile compound showed a high contribution of 1-octen-3-ol and 3-methyl-2,4-dithiapentane to the odor of T. japonicum. Although 2,4-dithiapentane is a key odorant of well-known white truffle T. magnatum, 3-methyl-2,4-dithiapentane was detected from the ripe T. japonicum. The chemical components of T. japonicum showed no clear difference with those of edible truffles T. magnatum and T. melanosporum. It was rich in crude protein, crude fiber, and minerals (especially potassium), and low in crude fat. Glutamine and glutamic acid were detected in T. japonicum as free amino acids, while T. magnatum contained a large amount of alanine. Acute oral toxicity tests showed no abnormality, with an LD50 value of over 2000 mg/kg under the test conditions. The present study may support future market distribution of T. japonicum as a high-class foodstuff.