A key lock structure arranged in a mechanical key lock device refusing any code pressing while locked, so as to avoid finding out the correct codes by try and error. The key lock structure includes a casing, a sliding base disposed in the casing, an orientation frame arranged on a bottom face of the sliding base and a plurality of code-locked keystroke bodies. The sliding base has a plurality of elongation arms parallel to one another, a plurality of slots arranged with the elongation arms in an alternate manner, and a plurality of stop portions disposed in the respective slots. The orientation frame is disposed under the sliding base. Each of the code-locked keystroke bodies has a sliding member, which has an extrusion portion capable of being blocked by the respective stop portion. Consequently, the code-locked keystroke bodies are fixed and cannot be pressed in the lock status.