The present invention provides a method to improve the optical purity of 1-benzyl-3-aminopyrrolidine having a low optical purity using an inexpensive agent via a simple procedure. The present invention provides a method for improving the optical purity of 1-benzyl-3-aminopyrrolidine including the steps of converting 1-benzyl-3-aminopyrrolidine into an equimolar salt with an optically inactive acid, and recovering the salt as crystals. The present invention also provides a salt of 1-benzyl-3-aminopyrrolidine that is used in the method.