Steviol methyl ester (methyl ent-13-hydroxykaur-16-en-19-oate)* was converted into five new metabolites together with a known compound, methyl ent-7α,13-dihydroxykaur-16-en-19-oate, by Gibberella fujikuroi in the presence of a plant growth retardant. The structures of these new metabolites were elucidated to be methyl ent-7β,13-dihydroxykaur-16-en-19-oate, methyl ent-11α,13-dihydroxykaur-16-en-19-oate, methyl ent-7β,11α,13-trihydroxykaur-16-en-19-oate, methyl ent-11α, 13,15β-trihydroxykaur-16-en-19-oate and methyl ent-13,15β-dihydroxy-11-oxokaur-16-en-19-oate mainly by spectroscopic analyses.