An unstretched cellulose acylate film is stretched in a ratio ranging from 1.05 to 1.6 in the longitudinal direction (MD) in a longitudinal stretching section using at least two rollers having a surface-to-surface separation of 2 to 50 mm therebetween and being different in circumferential velocity, thereafter the cellulose acylate film stretched in the longitudinal direction is heated in the heat treatment section to a temperature ranging from Tc to Tc+80.degree. C. under the conditions that the widthwise ends of the cellulose acylate film are gripped, and thus the cellulose acylate film is contracted in the widthwise direction (TD) to produce the intended cellulose acylate film. This method can provide a cellulose acylate film having properties suitable for an optical film and so on.