A blood reservoir being capable of reducing damage to blood stored therein. The
blood reservoir has a housing in the form of a box, and filtering and defoaming
devices provided in the housing, i.e., a device for filtering and defoaming on
blood suctioned from a surgical field (outside a heart), a device for filtering
and defoaming on blood vented from the interior of the heart, and a device for
filtering and defoaming on blood drawn off from a large vein. The vented blood
flowing into the blood reservoir passes through a vented blood filtering member
to be introduced into a blood storage space without contacting an antifoaming agent
and foreign substances filtered off from the suctioned blood.
