Analytical procedures for trace elements in rocks (Ba, Co, Cr, Cu, Nb, Ni, Rb, Sr, V, Y, Zn, Zr), using an X-ray fluorescence analyzer (RIGAKU RIX3000) at the National Institute of Polar Research, are summarized. Samples are fused with Li_2B_4o_7 (weight proportion of 1 : 5) to prepare glass bead in order to avoid analytical errors caused by mineralogical effect, grain size effect and segregation. The results were satisfied with correcting spectral line overlap, interference X-ray of heavy elements, and matrix effect by means of peak-over-back method.