Chronic otitis media is one of the common diseases in the ENT field. Bony erosion is considered as an important factor that has been thought to be a progression of disease and complication in chronic otitis media. Recently, we think, high resolution computed tomography of the temporal bone is the most accurate diagnostic tool and is more popularly used. Various theories were introduced to understand how bony erosion in chronic otitis media occurs. Many enzymes are elaborated or activated by the multinucleated osteoclast, and acid phosphatase is one of the enzymes we are considering. We compared operative findings in middle ear surgery with high resolution computed tomography of the temporal bone & serum acid phosphatase/alkaline phosphatase increment ratio in order to investigate clinical usefulness of high resolution computed tomography of temporal bone and comeasurement of serum acid phosphatase/alkaline phosphatase increment ratio in middle ear surgery. According to the study result, a high degree of correct correlation between findings in high resolution computed tomography of the temporal bone and those of the operation. In addition to, serum acid phosphatase/alkaline phosphatase increment ratio was statistically significant in group 5(p<0.05). So, we concludes that high resolution computed tomography of temporal bone & comeasurement of serum acid phosphatase/alkaline phosphatase provide more preoperative information in some cases than high resolution computed tomography of temporal bone alone in chronic otitis media.