The present invention aims to provide a freeze-dried preparation in which the influenza vaccine exhibits improved stability. A freeze-dried preparation in which the influenza vaccine exhibits significantly improved stability can be obtained by freeze-drying an aqueous solution that meets the following conditions (A) to (C): (A) (i) an influenza vaccine, (ii) a hydrophobic amino acid, and (iii) arginine and an acid addition salt thereof are incorporated (B) the proportion of the component (iii) is from 20 to 85% by weight relative to the total amount of the resulting freeze-dried preparation and (c) the pH is adjusted to be from 8 to 10 by controlling the proportion of arginine and an acid addition salt thereof that form the component (iii).
