Disassembly-prevention device of an automatic handgun, having - a disassembly shaft that is disposed within the grip and that by means of an external handle is rotatable between a blocking position for blocking the barrel and a disassembly position for disassembling the barrel; - a disassembly-prevention element that is movable between a locking and a releasing position, and o said disassembly-prevention element in the locking position thereof by way of a first end engaging in the disassembly shaft and, on account thereof, securing the latter in the blocking position thereof, and said disassembly-prevention element in the releasing position thereof by way of the first end thereof being disengaged from the disassembly shaft, releasing the latter for rotation to the disassembly position thereof; and o said disassembly-prevention element at the second end thereof being impinged by a magazine that is inserted into the automatic handgun and, on account thereof, being moved to the locking position thereof, and in the case of a fully or partially removed magazine being movable to the releasing position thereof, characterized in that the disassembly-prevention element, in order to assume the locking position or the releasing position thereof, is mounted so as to be pivotable about a rotation axis. - a disassembly shaft that is disposed within the grip and that by means of an external handle is rotatable between a blocking position for blocking the barrel and a disassembly position for disassembling the barrel; - a disassembly-prevention element that is movable between a locking and a releasing position, and o said disassembly-prevention element in the locking position thereof by way of a first end engaging in the disassembly shaft and, on account thereof, securing the latter in the blocking position thereof, and said disassembly-prevention element in the releasing position thereof by way of the first end thereof being disengaged from the disassembly shaft, releasing the latter for rotation to the disassembly position thereof; and o said disassembly-prevention element at the second end thereof being impinged by a magazine that is inserted into the automatic handgun and, on account thereof, being moved to the locking position thereof, and in the case of a fully or partially removed magazine being movable to the releasing position thereof, characterized in that the disassembly-prevention element, in order to assume the locking position or the releasing position thereof, is mounted so as to be pivotable about a rotation axis. o said disassembly-prevention element in the locking position thereof by way of a first end engaging in the disassembly shaft and, on account thereof, securing the latter in the blocking position thereof, and said disassembly-prevention element in the releasing position thereof by way of the first end thereof being disengaged from the disassembly shaft, releasing the latter for rotation to the disassembly position thereof; and o said disassembly-prevention element at the second end thereof being impinged by a magazine that is inserted into the automatic handgun and, on account thereof, being moved to the locking position thereof, and in the case of a fully or partially removed magazine being movable to the releasing position thereof, characterized in that