To freeze a leaf vegetable by a simple operation so as to improve excellent shelf stability and to obtain a high nutritive value and excellent texture by cleaning the leaf vegetable, preserving in salt, dehydrating and quickly freezing the leaf vegetable.

A leaf vegetable is cleaned, the cleaned leaf vegetable is preserved in salt and dehydrated. The dehydrated leaf vegetable is quickly frozen. In the operation, in order to clean the leaf vegetable, preferably one or more of an aqueous solution of hypochlorous acid compound, an aqueous solution of chlorine dioxide, ozonous water and an aqueous solution of a cationic or amphoteric surfactant are used. Preferably, the freezing temperature is -20 to -60°C when the dehydrated leaf vegetable is quickly frozen.