A new androstane derivative, $4{eta}$-methyl-15-oxa-$14{eta}$-androstane-7-ene-$4{alpha}$-carboxylic acid (1) and a known one $4{eta}$-methyl-15-oxa-$14{eta}$-androstane-7-ene-$4{alpha}$-hydroxyl (2) were isolated from the EtOAc extract of the cultures of the fungus Marasmiellus ramealis (Bull.) Singer. Their structures were elucidated on the basis of 1D and 2D NMR as well as MS spectroscopic data analysis. The inhibitory activity of two isolates against acetylcholinesterase (AChE) revealed that compound 1 exhibited definitely inhibitory activity.