The medical bag 1 is composed of a flexible sheet material 21, and a bag body 2 that is partitioned into a first space 3 and a second space 4 via a partition portion 5, and a first bag It has the 1st liquid 30 stored in the space 3, and the 2nd liquid 40 stored in the 2nd space 4, and the partition part 5 is located in the perpendicular direction upper side rather than the sheet seat material 21, and surface An upper mold 81 having a temperature of 130 to 145 ° C. and a lower mold 82 that is positioned vertically lower than the sheet material 21 and whose surface temperature is 20 to 30 ° C. lower than the surface temperature of the upper mold 81 It is formed by fusing with the sheet material 21 interposed therebetween, and is obtained by sterilization at 118 to 125 ° C. for 20 to 45 minutes. The ratio L1 / L2 of the volume L1 of the first liquid 30 and the volume L2 of the second liquid 40 is 2.0 to 6.0, and the breaking strength of the partition part 5 is 5 to 25 kPa.医療用バッグ１は、可撓性を有するシート材２１で構成され、内部が仕切り部５を介して第１の空間３と第２の空間４とに仕切られたバッグ本体２と、第１の空間３に収納された第１の液体３０と、第２の空間４に収納された第２の液体４０とを有し、仕切り部５は、シート材２１よりも鉛直方向上側に位置し、表面温度が１３０～１４５℃である上金型８１と、シート材２１よりも鉛直方向下側に位置し、表面温度が上金型８１の表面温度よりも２０～３０℃低い下金型８２とでシート材２１を挟んで融着することにより形成され、１１８～１２５℃で２０～４５分、滅菌して得られたものである。第１の液体３０の体積Ｌ１と第２の液体４０の体積Ｌ２の比Ｌ１／Ｌ２は、２．０～６．０であり、仕切り部５の破断強度は、５～２５ｋＰａである。
