The utility model discloses an electric lantern microelectrode logging unit applied to engineering surveying construction of open hole microelectrode curves in petroleum logging industry and belongs to the technical field of petroleum logging instruments. The logging unit comprises a first cylindrical pin, a second cylindrical pin, a third cylindrical pin, a fourth cylindrical pin, a first bow spring steel plate and a second bow spring steel plate. Before a polar plate reaches a to-be-measured target stratum, the bow spring steel plates are in a folded state, and therefore, the risk that the polar plate meets resistance during a construction process is reduced, and further, the damage of the polar plate is reduced. When logging is performed by the logging unit, the bow spring steel plates are arched outwards, and therefore, a better wall contacting effect is obtained by the polar plate.