Recovery of nitrogen heterocyclic compounds (NHC) contained in coal tar oil fraction was investigated by cocurrent five stages equilibrium extraction. The aqueous solution of formamide was used as a solvent. NHC (particularly, indole) was recovered as much as 99% by cocurrent four stages equilibrium extraction. Maximum selectivity of indole based on 2-methylnaphthalene (2MN) obtained through cocurrent three stages equilibrium extraction was 54. The sequence of the distribution coefficient and selectivity based on 2MN for each component of NHC was indole>iso-quinoline≥quinoline>quinaldine. Extraction method using the aqueous solution of formamide as a solvent was estimated superior separation method in terms of the separation performances for NHC (particularly, indole) contained in coal tar oil fraction.