There is provided a blood-collecting initial flow removing bag and a blood-collecting initial flow removing set, by which an initial flow blood is collected, the blood for testing is easily extracted, and the blood is easily moved due to capillary action. First to third partitions (P1, P2, P3) and an air-guiding part (R) are configured as substantially linear partitions (dividing walls) so as to clearly section an interior of a bag body (21), and are configured in a substantially annular pattern which continuously extends around in a direction from a blood inlet (23), a direction toward a (right) side part, a direction toward a bottom part, a direction toward a (left) side part of the bag body (21), and returning in a direction toward the blood inlet (23) again.設置一種採血初流去除袋及一種採血初流去除組,藉此採集初流血液,容易地抽取測試用血液,且血液由於毛細管作用而容易移動。第一至第三隔壁(P1、P2、P3)及一空氣導引部分(R)被組態成實質上線性隔壁(分割壁)以便明確地分隔一袋本體(21)之內部,且以一實質上環狀圖案被組態,該圖案在來自一血液入口(23)之一方向、朝向該袋本體(21)的一(右)側部分之一方向、朝向一底部部分之一方向、朝向一(左)側部分之一方向上連續地環繞延伸,且再次在朝向該血液入口(23)之一方向上返回。