The problem to be solved in the present invention is to provide a kind of novel pharmaceutical composition, containing Dorzolamide or its salt and Brimonidine or its salt and shows sufficient anti-corrosion effect. Pharmaceutical composition according to the present invention, it is 6. that containing, which has pH for Dorzolamide or its salt and Brimonidine or its salt,0 or bigger. Pharmaceutical composition of the invention is preferably free of preservative or including predetermined amount, wherein the quota is preferably, so that the bacterium of the quantity (component B) of the ratio (aviation office) of logarithm, be seeded to number (one) bacteriums when viable count measurement sample after access strain, it is uniformly mixed applied to including preservative and water, it is 105-106 bacterium numbers with the Escherichia coli bacteria suspension that concentration is ATCC 8739, seven days whether have been stored at 20-25 °C in sample with micropipette with 1 milliliter of sample is collected, when being 2. in light shield0 or smaller.
