To prevent a user from accidentally pricking the user with a hollow needle when separating blood components using a syringe and a connection device. A blood component separation apparatus has three syringes and a connection device. The connection device is attached to one syringe and is inserted into other syringes. The connection device has a first member to which a base end of a hollow needle is joined and a second member which is connected to the first member in such a manner as to be able to move relative to the first member. The second member is moved back and forth between a first position where a tip of the hollow needle is accommodated and a second position where the tip of the hollow needle is exposed. The second member has elastic portions which are elastically deformed in the movement from the first position to the second position. The elastically deformed elastic portions elastically energize the second member at the second position to the first position side with respect to the first member.
