We report a novel technology, called InCell IT, for in situ monitoring of bindings between a small molecule kinase inhibitor and its target protein kinases in live cells using a kinase inhibitor, dasatinib, as a model compound. Streptavidin-attached MNPs were coated by biotinylated dasatinib, and then these dasatinib-MNPs were transferred into cells. In the cells, the MNPs were aligned to the same direction of the magnetic field and EGFP-tagged target protein kinases were bound to dasatinib-MNPs. Using this technology, we demonstrated the bindings between dasatinib and its target protein kinases including SRC, ABL1, and CSK in live cells. The specificity of these bindings was also confirmed by cold competition using unbiotinylated dasatinib in the same cells.