We have performed a long-slit K-band spectroscopic observation of the luminous infrared galaxy NGC 6240. Spatially extended H2 emission is detected over 3.3 kpc around the two nuclei. The peak position of the H2 v = 1-0 S(1) emission is located at ∼ 0″.3-0″.4 north of the southern nucleus. Based on line-ratio analyses, we suggest that the excitation mechanism of H2 is pure thermal at most positions. We find the following three velocity components in the H2 emission around the southern nucleus and its south region: a blue-shifted component (â‰).