A cable management arm, comprising: a first cable management mechanism including: a first arm member; a second arm member movably connected to the first arm member; a first connecting device movably connected to the first arm member and a second connecting device movably connected to the second arm member;, a second cable management mechanism including: a first arm member; a second arm member movably connected to the first arm member; a first connecting device movably connected to the first arm member, and a second connecting device movably connected to the second arm member; characterized in that the first connecting device of the first cable management mechanism further includes a first connecting section, a second connecting section, and a passage at the first connecting section; and that the first cable management mechanism further includes a supporting bracket connected to the second connecting section; and that the first connecting device of the second cable management mechanism further includes an extension; and that the cable management arm further comprises a first supporting mechanism and a second supporting mechanism, wherein the first supporting mechanism includes: a first supporting rail for supporting one of the first arm member and the second arm member of the first cable management mechanism; a second supporting rail telescopically connected to the first supporting rail; a movable member connected to the first supporting rail, the movable member being movably mounted to the passage of the first connecting device of the first cable management mechanism; and a fastener connected to the second supporting rail; wherein the second supporting mechanism includes: a first supporting rail for supporting one of the first arm member and the second arm member of the second cable management mechanism; a second supporting rail telescopically connected to the first supporting rail; a movable member connected to the first supporting rail, the movable member being movably mounted to the first connecting device of the second cable management mechanism; and a fastener connected to the second supporting rail, the fastener being releasably mounted to the supporting bracket of the first cable management mechanism; and wherein the second cable management mechanism further includes a supporting bracket connected to the extension, the supporting bracket being releasably connected to the fastener of the first supporting mechanism. a first cable management mechanism including: a first arm member; a second arm member movably connected to the first arm member; a first connecting device movably connected to the first arm member and a second connecting device movably connected to the second arm member;, a second cable management mechanism including: a first arm member; a second arm member movably connected to the first arm member; a first connecting device movably connected to the first arm member, and a second connecting device movably connected to the second arm member; characterized in that the first connecting device of the first cable management mechanism further includes a first connecting section, a second connecting section, and a passage at the first connecting section; and that the first cable management mechanism further includes a supporting bracket connected to the second connecting section; and that the first connecting device of the second cable management mechanism further includes an extension; and that the cable management arm further comprises a first supporting mechanism and a second supporting mechanism, wherein the first supporting mechanism includes: a first supporting rail for supporting one of the first arm member and the second arm member of the first cable management mechanism; a second supporting rail telescopically connected to the first supporting rail; a movable member connected to the first supporting rail, the movable member being movably mounted to the passage of the first connecting device of the first cable management mechanism; and a fastener connected to the second supporting rail; wherein the second supporting mechanism includes: a first supporting rail for supporting one of the first arm member and the second arm member of the second cable management mechanism; a second supporting rail telescopically connected to the first supporting rail; a movable member connected to the first supporting rail, the movable member being movably mounted to the first connecting device of the second cable management mechanism; and a fastener connected to the second supporting rail, the fastener being releasably mounted to the supporting bracket of the first cable management mechanism; and wherein the second cable management mechanism further includes a supporting bracket connected to the extension, the supporting bracket being releasably connected to the fastener of the first supporting mechanism.