Experimental results of the p( 13 B, d) 12 B transfer reaction to the low-lying states in 12 B are reported. The optical potential parameters for the entrance channel are extracted from the elastic scattering p( 13 B, p) measured in the same experiment, while those for the exit channel are global ones. Spectroscopic factors associated with the p-, s-, and d-wave neutron transfer to the known 12 B states, are extracted by comparing the deuteron angular distributions with the calculation results. The separated s-and d-wave intruder strengths in 13 Bg.s. were determined to be 10(2)% and 6(1)%, respectively, which follow roughly the systematics for the N = 8 neutron-rich isotones. The measured total intruder strength is in good agreement with the shell model calculation, while the individual ones evolve quite differently. Particularly, the sudden change of the d-wave intensity between 13 B and 12 Be needs further theoretical interpretation.