B[E] STARS .3. MWC-645

We analyse spectroscopic CCD material obtained at the Haute Provence O bservatory. We provide identifications and equivalent width measuremen ts in the wavelength region 3740-8790. About 350 emissions lines were measured and about 88 of them were identified. A comparison of our res ults with those of other authors is provided, as well as a table of el ements identified in the spectrum of this star. The pattern of element s present is analogous to that of a late B-type star, but some excepti ons are noted, such as the absence of Ne and Mg lines and the presence of K, Cu and Zr lines which appear usually in later type stars. We re view the little which is known concerning this object and we also pres ent a quantitative account of the variations in equivalent widths. The observations indicate that the spectrum is highly variable, so that i n two different years only half of the lines appear on both spectra. F urthermore variations by at least a factor of two in the equivalent wi dths are present in many lines. The radial velocity derived from the e mission lines (-76 km/s) corresponds to that of the shell which probab ly has a velocity of about 50 km/s with respect to the underlying star .