A method for performing geomagnetic signal processing using a geomagnetic signal processing apparatus is provided. The method includes obtaining a geomagnetic signal based on a geomagnetic sensor output; converting the obtained geomagnetic signal into a high frequency signal having a frequency equal to or higher than a reference frequency using a signal processing filter; extracting abnormal high frequency signal values outside a predetermined critical range from the converted high frequency signal; determining whether a sum of the extracted abnormal high frequency signal values converges into a critical range a preset time window; and correcting the geomagnetic signal based on the determining.