A rack collecting unit (7, 70) usable in a first sample processing apparatus and a second sample processing apparatus, wherein the first sample processing apparatus transports a sample rack sent out from a rack setting unit to a rack collecting unit (7, 70) through a sample processing unit using a first transport path (206, 216) for transporting the sample rack in a first direction, and the second sample processing apparatus transports the sample rack sent out from the rack setting unit to a sample processing unit using a first transport path for transporting the sample rack in the first direction and thereafter transports the sample rack to the rack collecting unit (7, 70) using a second transport path (207, 217) for transporting the sample rack in a second direction opposite to the first direction, the rack collecting unit (7, 70) comprising: a storing section (711, 721, 731) for storing therein the sample rack; characterised in that: the rack collecting unit (7, 70) further comprises: a third transport path connectable to the first transport path (206, 216) and capable of transporting the sample rack in the first direction; a fourth transport path connectable to the second transport path (207, 217) and capable of transporting the sample rack in the second direction; and a transferring section for transferring the sample rack carried onto the third transport path or the fourth transport path to the storing section (711, 721, 731), in that: the third transport path and the fourth transport path are arranged in parallel with each other, and in that: the transferring section transfers the sample rack in a direction orthogonal to the transport directions of the sample rack transported by the third transport path and the fourth transport path. a storing section (711, 721, 731) for storing therein the sample rack; characterised in that: the rack collecting unit (7, 70) further comprises: a third transport path connectable to the first transport path (206, 216) and capable of transporting the sample rack in the first direction; a fourth transport path connectable to the second transport path (207, 217) and capable of transporting the sample rack in the second direction; and a transferring section for transferring the sample rack carried onto the third transport path or the fourth transport path to the storing section (711, 721, 731), in that: the third transport path and the fourth transport path are arranged in parallel with each other, and in that: the transferring section transfers the sample rack in a direction orthogonal to the transport directions of the sample rack transported by the third transport path and the fourth transport path. a third transport path connectable to the first transport path (206, 216) and capable of transporting the sample rack in the first direction; a fourth transport path connectable to the second transport path (207, 217) and capable of transporting the sample rack in the second direction; and a transferring section for transferring the sample rack carried onto the third transport path or the fourth transport path to the storing section (711, 721, 731), in that: the third transport path and the fourth transport path are arranged in parallel with each other, and in that: the transferring section transfers the sample rack in a direction orthogonal to the transport directions of the sample rack transported by the third transport path and the fourth transport path.