We made sharp optical fiber tips with less than 100 nm diameter by using the heating and pulling method with a good repetition and fabricated the photon scanning tunneling microscope (PSTM) using constant intensity mode. The 3-dimensional PZT (Piezoelctric transducer) scanner made of a long PZT tube is consisted of three divided parts, that is, a pair of $pm$ x and a pair of $pm$y scanning parts and a z scanning part for the fine approach and scanning. The scanning dimension is 1.43 $mu extrm{m}$$ imes$1.76 $mu extrm{m}$. The height of a optical tip to maintain a constant height within $1/{lambda}_0$ (${lambda}_0$ is the incident wavelength) from surface of a specimen to a optical tip is controlled automatically by using the electric feedback circuit. The 3-dimensional shape of standing evanescent waves generated on the surface of a dove prism was measured successfully by using the constant intensity mode PSTM.