Extracts of the heatwood of Juniperus formosana HAYATA were found to contain the known constituents β-sitosterol, α-cedrol, 4-ketocedrol, 3βhydroxycedrol, isocedrolic acid, δ-cadinol, cadin-8-en-10-ol, clovandiol, sugiol, Δ⁵-dehydrosugiol, totarol, 7-oxototarol, cryptojaponol, emodin, and methyl α-conidendral, together with five new compounds, 7α-methoxydeoxocryptojaponol, suginal, detetrahydroconidendrin, formosanol, and junipediol. In addition, 7β-hydroxydeoxocryptojaponol was obtained (first isolation as a natural product). Junipediol has a novel sesquiterpene skeleton which was elucidated by X-ray analysis.