Provided is a blood reservoir equipped with a filter having a treatment capacity desired by a health worker. A health worker managing a blood reservoir can comprehend the amount of stored blood more accurately. Furthermore, bubbles are prevented from being mixed into blood after bubbles are removed therefrom. A filter member (52) of a blood reservoir (1) is a filter member for removing foreign matters and bubbles from the blood. The filter member (52) is equipped with a first filter portion (52a) and a second filter portion (52b). The first filter portion (52a) forms the wall portion and the second filter portion (52b) forms the bottom portion. Specifications of the first filter portion (52a) and the second filter portion (52b) are different. The guide member (60) of the blood reservoir (1) consists of foaming material. The blood from which bubbles are removed are thereby led in a state where the blood permeated the guide member (60). Consequently, the guide member (60) can lead the blood from which bubbles are removed to a predetermined position at an appropriate landing speed.
