An industrially advantageous process for producing optically active 4-amino-2-methylbutane-1-ol which is useful as an intermediate in synthesizing optically active medicines and pesticides. Racemic 4-amino-2-methylbutane-1-ol is treated with an optically active organic acid. The diastereomeric salt thus obtained is crystallized out and subjected to solid-liquid separation to give optically active 4-amino-2-methylbutane-1-ol. The diastereomeric salt of optically active 4-amino-2-methylbutane-1-ol with an optically active reagent for optical resolution is decomposed by bringing into contact with a solvent and an alkali and subjected to solid-liquid separation, thereby recovering the optically active 4-amino-2-methylbutane-1-ol from the filtrate. Further, the filtration residue containing the alkali salt of the reagent for optical resolution obtained by the solid-liquid separation is brought into contact with a solvent and an acid. Then the reagent for optical resolution thus crystallized out is subjected to solid-liquid separation and recovered.