PURPOSE: To increase a container capacity during a hot filling and to prevent a spilling accident of contents by constituting a part of the container wall with a shape memory material which has a specific characteristic to store a protruding shape to the inside of the container.

CONSTITUTION: For example, in a case that a predetermined amount of a coffee 6 heated upto a temperature T2 in a temperature zone S1 which is a specific zone of a temperature higher than a critical temperature T1 of a shape memory piece 3, is poured into a variable capacity container 1, of which a bottom has a shape of a spherical surface, protrudes to an inside of the container and is formed by the shape memory piece 3. Consequently, a can barrel piece 2 of which a critical temperature is higher than T2, stays at a glassy phase and keeps its shape, and only the shape memory piece 3 changes itself to a rubbery state and deforms its shape protrudingly to an outside so that the container capacity and a head space increase according to a weight of the coffee 6, and therewith the coffee 6 does not spill out easily during being transferred. In this condition, a lid 8 is fastened with double-seaming. When being turned upside down, e shape memory piece 3 in which a load W is unloaded, returns to a memorized shape. When cooled down to a temperature lower than T1 at this condition, the shape memory piece 3, too, changes itself to a glassy state and the container 1 keeps a last shape mentioned above, thereafter.