PROBLEM TO BE SOLVED: To provide connection members (1, 1, 1) capable of clarifying the variation (discrimination) of an opening/closing operation of liquid flow paths LP of an adaptor 10 and a mixed-injection member 20.SOLUTION: A connection tool includes a connection adaptor 10 and connection covers (5, 5, 5). In the connector adaptors (10, 10), a pair of locking parts (12K, 12K) project in two directions of a side part S of on an end DE side of a middle part 12. The connection covers (5, 5, 5) form a pair of upper passages 5 PU in the two directions of the side part S over from an upper side of an upper part 5U inner wall to a lower side, and form a pair of engaging parts (5TD, 5UMD) in the two directions of the side part S on a lower part D side of the upper part 5U inner wall. The locking parts (12K, 12K) of the adaptors (10, 10) are inserted from the upper passages 5 PU of the connection covers (5, 5, 5), turned from the two directions of the side part S to two directions of the other side part S by about 90 degrees, and fixed by engaging the engaging parts (5TD, TUMD) with the locking parts (12K, 12K).
