Imaging performance in a confocal fluorescent microscope can be improved by using multiple detectors. The use of a large detector radius in a confocal fluorescent microscope, while giving a strong signal for lower spatial frequencies, results in negative components at some higher frequencies. Using this fact, effects of a simple detector array consisting of the difference signal between small and large detectors are considered. The effects on the transverse and axial variation of the three-dimensional optical transfer functions (OTFs) of the confocal fluorescent microscope are considered. The results show that the resulting OTFs are boosted, resulting in a better resolution.