An object is to provide a blood collection set configured such that a sampling holder and a needlestick-preventive needle cover are more difficult to disengage from each other than conventional. A blood collection set (500) includes a sampling holder (100) and a needlestick-preventive needle cover (200). The sampling holder (100) includes a tubular body (110), a lid (130), and a fitting portion (140) having a circumferential rib as a rib portion and a catching portion. The neediestick-preventive needle cover (200) includes an engaging portion (250) that is engageable with the catching portion of the sampling holder (100).
