PURPOSE: To provide the title freezing process so designed that an anti-freeze with its specific gravity at cooling temperatures smaller than that of the biological tissue before freezing but greater than that of said tissue after freezing is used, thereby sinking the object to be freezed into an anti-freeze tank and then making the object freezed float without the need for using any device or equipment.

CONSTITUTION: A sealed container 12 containing a biological tissue 10 is fitted with a weight 14 and made, as a whole, its specific gravity before freezing greater than that of an anti-freeze, but said specific gravity after freezing smaller than that of said anti-freeze. The object to be freezed sinked into the anti-freeze due to specific gravity difference floats on the level of said anti- freeze because of its volume increase due to freezing.