The main function of a debugger in programming is to identify and resolve errors or bugs within code. Debuggers allow developers to execute code step-by-step, observing its operations and inspecting variables at various points to trace issues. By providing tools such as breakpoints and watchpoints, debuggers help programmers quickly locate problematic sections of code. This process is crucial for ensuring that software runs efficiently and correctly, ultimately enhancing code quality and reducing the time spent on troubleshooting and fixing issues.