The present invention fits the fitting through the square hole drilled so that the rectangular fitting can be tightly fitted to the connecting piece which was fitted with the existing iron wire spring so that the door lock cannot be detached from the outside arbitrarily using a tool such as a cellar. By attaching a relatively wide plate-shaped leaf spring by the mounting holes of the shims, it is possible to completely prevent the both ends of the spring from being broken or easily pulled out in the square hole as in the prior art, so that the door lock can not be released arbitrarily. It is to provide an anti-freeze door lock.
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