The object is to produce an azabicycloalkanol derivative, particularly a cis-3-substituted-3-azabicyclo[3.2.1]octan-8-ol derivative which is a useful intermediate for agricultural chemicals or pharmaceutical agents, with a good yield and at an industrially low cost. A diastereomer of an azabicyclo-C6-10-alkanol derivative having a methyne substituted a hydroxyl group as an asymmetric carbon (e.g., a trans-3-substituted-3-azabicyclo[3.2.1]-8-ol derivative) is isomerized in the presence of a transition metal complex, thereby producing an excess amount of a thermodynamically more stable one of diastereomers (e.g., a cis-3-substituted-3-azabicyclo[3.2.1]-8-ol derivative). In this manner, a thermodynamically more stable one of diastereomers of the azabicyclo-C6-10-alkanol derivatives can be produced.