The present invention provides for a method of selecting an antibody against a target substance to be measured, which comprises selecting the antibody against the target substance by antigen-antibody reaction in the presence of a substance interfering with the antigen-antibody reaction. That is, an antigen and a labeled antigen are reacted with the antibody in the presence of an interfering substance, such as an environment pollutant, and on the basis of the degree of reaction thereof, the antibody against the target substance, which is highly resistant to the interfering substance, is selected. Thereby, even if a test sample is contaminated with a substance interfering with antigen-antibody reaction, the antibody, which is highly resistant to the substance interfering with antigen-antibody reaction, is not influenced by the interfering substance and gives a correct value in the quantification. The present invention further provides for antibodies, which are highly resistant to the substance interfering with the antigen-antibody reaction, and hybridomas producing the antibodies.