Rada strejdy Googla (předpokládám, že máš Windows):

Reversing mouse scrolling direction
To reverse the mouse scrolling direction using the Registry, use these steps:

Use the Windows key + R keyboard shortcut to open the Run command.
Type regedit, and click OK to open the Registry.
Browse the following path:

Computer\HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Enum\HID

Quick tip: On Windows 10, you can now copy and paste the path in the Registry's address bar to quickly jump to the key destination.

Expand the key (folder) that matches the VID ID of your mouse — for example, VID_0E0F&PID_0003&MI_01.

Expand the available key.
Select the Device Parameters key.
Double-click the FlipFlopWheel DWORD and set the value from 0 to 1.

Click OK.
Restart your computer.