From the mature plant of Fritillaria camtschatcensis Ker-Gawlr, a new alkaloid named hapepunine (1) was isolated in addition to solanidine, tomatidenol (3), and solasodine (4). The structure of hapepunine was determined as N-methyl-22,26-epiminocholest-5-ene-3β,16β-diol by means of elementary analysis, spectral data (NMR, MS), and comparison with derivatives of tomatidenol and solasodine. Hapepunine is the first naturally occurring 16β-hydroxy-22,26-epiminocholestane derivative, and it appears to be synthesized from tomatidenol in the aerial part by biological degradation rather than from the precursor of spirosolane biosynthesis.