Abstract: An artificial organ embodying this invention is adapted for heat sterilization and allows for simple aftertreatment following said heat sterilization. The artificial organ is previously filled with a solution (8) harmless to the human body. A liquid pressure-buffering tube holding such an amount of gas as is capable of quantitatively absorbing the expansion of said solution (8) occurring during the heat sterilization of the artificial organ is connected to at least one of liquid ports (3), (4), (5), (6) communicating with the interior of the artificial organ. A process embodying the invention for heat sterilizing an artificial organ simplifies aftertreatment of said artificial organ following said heat sterilization, and comprises the steps of vacuum packaging the whole artificial organ device and heat sterilizing the artificial organ device while a gas held in the liquid pressure-buffering tube (2) is kept in the upper part of said artificial organ device.