The present invention provides a method for purifying HFO-1234yf, comprising the steps of (1) cooling a liquid mixture containing HFO-1234yf and HF to separate the mixture into a upper liquid phase having a high concentration of HF and a lower liquid phase having a high concentration of 2,3,3,3-tetrafluoropropene; and (2) subjecting the lower liquid phase obtained in step (1) to a distillation operation to withdraw a mixture containing HFO-1234yf and HF from a top of a distillation column, thereby obtaining substantially HF-free HFO-1234yf from a bottom of the distillation column. According to the present invention, HF and HFO-1234yf contained in a mixture containing HF and HFO-1234yf can be separated under simple and economically advantageous conditions.