In the method for separating and purifying a basic amino acid, preferably the basic amino acid selected from arginine, lysine or ornithine from a culture containing the amino acid, the culture containing the a basic amino acid and microbial cells, preferably the culture whose pH is 4 to 10, is charged onto the top of a column filled with a weak acid cation exchange resin whose particle size is 300 μm or more and passed therethrough, and then an eluent is poured into the column from the top thereof whereby accomplishing the separation and the purification of the basic amino acid.