Extension device and electronic system

An electronic system, comprising:

• an electronic device, comprising a buckle groove;
• and
• an extension device, comprising:
• a connecting base, comprising:
• a housing;
• a first moving member, disposed at the housing, capable of moving back and forth along a direction to be located at a buckling position or a releasing position, and comprising a main body and a hook extending from the main body and exposed outside the housing, wherein the hook is disposed corresponding to the buckle groove of the electronic device, so that the electronic device is assembled to the connecting base by the buckle groove engaged with the hook;
• a fixed member, disposed at one side of the housing and comprising a lock hole;
• and
• a second moving member, movably disposed between the main body and the fixed member;
• and
• an anti-theft lock assembly, detachably disposed at one side of the fixed member opposite to the second moving member, wherein when the electronic device is assembled to the connecting base and the hook is located at the buckling position, the anti-theft lock assembly is adapted to pass through the lock hole of the fixed member and push against the second moving member, so that the second moving member moves towards and abuts against the main body to stop the first moving member at the buckling position,
• when the first moving member is located at the buckling position, a gap is presented between the second moving member and the main body.