A slide rail mechanism, comprising: a rail member comprising an upper wall, a lower wall and a longitudinal wall connected between the upper wall and the lower wall; a supporting member, the supporting member and the rail member capable of moving relative to each other along a longitudinal direction, the supporting member comprising an upper supporting portion, a lower supporting portion and a longitudinal portion connected between the upper supporting portion and the lower supporting portion; a first bracket, the first bracket and the supporting member capable of moving relative to each other along the longitudinal direction; and a fastening member capable of in one of a first state and a second state relative to the first bracket; wherein the upper supporting portion of the supporting member wraps a portion of the upper wall of the rail member, and the lower supporting portion of the supporting member wraps a portion of the lower wall of the rail member; wherein when the supporting member is moved from a first position to a second position relative to the first bracket, the supporting member is capable of driving the fastening member to change from the first state to the second state characterized in that: an auxiliary member is connected to the supporting member, the first bracket is movably mounted to the auxiliary member; wherein one of the auxiliary member and the first bracket is arranged with a first structure, the other one of the auxiliary member and the first bracket is arranged with a second structure, when the supporting member is located at the second position, the supporting member is capable of being kept at the second position through cooperation between the first structure and the second structure; wherein one of the auxiliary member and the first bracket is arranged with a third structure, the other one of the auxiliary member and the first bracket is arranged with a fourth structure, when the supporting member is located at the second position, the supporting member is capable of being kept at the second position through cooperation between the third structure and the fourth structure. a rail member comprising an upper wall, a lower wall and a longitudinal wall connected between the upper wall and the lower wall; a supporting member, the supporting member and the rail member capable of moving relative to each other along a longitudinal direction, the supporting member comprising an upper supporting portion, a lower supporting portion and a longitudinal portion connected between the upper supporting portion and the lower supporting portion; a first bracket, the first bracket and the supporting member capable of moving relative to each other along the longitudinal direction; and a fastening member capable of in one of a first state and a second state relative to the first bracket; wherein the upper supporting portion of the supporting member wraps a portion of the upper wall of the rail member, and the lower supporting portion of the supporting member wraps a portion of the lower wall of the rail member; wherein when the supporting member is moved from a first position to a second position relative to the first bracket, the supporting member is capable of driving the fastening member to change from the first state to the second state characterized in that: an auxiliary member is connected to the supporting member, the first bracket is movably mounted to the auxiliary member; wherein one of the auxiliary member and the first bracket is arranged with a first structure, the other one of the auxiliary member and the first bracket is arranged with a second structure, when the supporting member is located at the second position, the supporting member is capable of being kept at the second position through cooperation between the first structure and the second structure; wherein one of the auxiliary member and the first bracket is arranged with a third structure, the other one of the auxiliary member and the first bracket is arranged with a fourth structure, when the supporting member is located at the second position, the supporting member is capable of being kept at the second position through cooperation between the third structure and the fourth structure. an auxiliary member is connected to the supporting member, the first bracket is movably mounted to the auxiliary member; wherein one of the auxiliary member and the first bracket is arranged with a first structure, the other one of the auxiliary member and the first bracket is arranged with a second structure, when the supporting member is located at the second position, the supporting member is capable of being kept at the second position through cooperation between the first structure and the second structure; wherein one of the auxiliary member and the first bracket is arranged with a third structure, the other one of the auxiliary member and the first bracket is arranged with a fourth structure, when the supporting member is located at the second position, the supporting member is capable of being kept at the second position through cooperation between the third structure and the fourth structure.