Abstract: An electron beam lithography apparatus having an external magnetic field correcting device comprises an electron gun for irradiating an electron beam onto a semiconductor wafer, a electron beam column made from a high magnetic permeability material disposed around the electron beam, a coil equipped on the electron beam column, a magnetic sensor for detecting an external magnetic field which is disposed at the outside of the electron beam column, a stage for mounting and moving the semiconductor wafer, a position detecting means for detecting the position mark on the stage, a correcting device for generating a correcting signal based on the outputs from the magnetic sensor and the position detecting means, and a current adjusting device for adjusting a correcting current flown into the coil according to the correcting signal from the correcting device so as to compensate a rotational deviation of the electron beam caused by the external magnetic field.