pair of calendering cylinders 19 is provided with a polished surface in engagement with the tubular knitted fabric as a function of the treated fabric type and of the calendering characteristics to be given when either due to the use of a different type of processed fabric or due to different end characteristics to be given to the fabric it is sufficient to disengage the first pair of calendering cylinders 19 and engage the second pair of calendering cylinders 20 whose surfaces are provided with the coating of textile material or the like according to the embodiment shown in fig2 a reel 12 is mounted on support frame 11 for the tubular knitted fabric 13 to be calendered alternatively the fabric is supplied from a stack provided on a bench on support frame 11 there are provided vertically and substantially parallel to each other both a first calendering unit generally indicated by numeral 14 and similar to that shown in fig1 and a second calendering unit indicated by numeral 15 in fig2 the elements which constitute the first calendering unit are designated by the same reference numerals as in fig1 a set of return rollers 21 and a compensator element 22 e g of swinging type which controls the tension of the tubular knitted fabric 13 are provided on the frame 11 so as to feed the tubular knitted fabric 13 are provided on the frame 11 so as to feed the tubular knitted fabric 13 to the second calendering unit 15 the second calendering unit 15 is essentially composed of a set of components.