The invention relates to a horizontal adjusting device used for a laboratory table. The horizontal adjusting device comprises a table body; the table body is provided with a pedestal; the table body and the pedestal are connected via a supporting rod; two gradienters, which are vertical to each other, are embedded into the pedestal; the lower four corners of the pedestal are all provided with wedge blocks; and the wedge blocks are arranged on the table body. The horizontal adjusting device is simple in structure, and is convenient to use; the pedestal is adjusted via moving of the wedge blocks, and is maintained at horizontal conditions, so that accuracy of measured data is ensured, error is avoided, and demands of people are satisfied.