Spectroscopy of ¹⁶B plays an essential role in understanding the halo structure in ¹⁷B, but very limited knowledge has so far been obtained. We have carried out a kinematically complete measurement on the spectroscopy of ¹⁶B by using quasi-free (p,pn) reaction on ¹⁷B. The level scheme of ¹⁶B up to 5 MeV was made clear for the first time