To provide a liq.-vapor contactor for separating air by the use of the separation technique of fractional distillation by which energy is saved by combining mass transfer and heat transfer or conducting the mass transfer and heat transfer at the same time.

This liq.-vapor contactor is provided with a vertical wall 64 arranged like the vertical plane of a cube. The contactor is furnished with plural vertical sheets 68 spaced in parallel. A packing formed by vertically arranging the corrugated liq.-vapor contact elements 52 and 56 used as a laminated packing is provided between each couple of adjacent sheets 68. The corrugated part of the element 52 is inclined to the bottom from the top in the opposite direction to the inclining direction of the adjacent element 56. Two outermost sheets 68 form the wall 64 of the contactor. The wall 66 is furnished with the opposed sheets 68 and the edge part of a spacer bar 70. The sheets 68 form a first set of passages 58 and a second set of passages 60. One set of passages perform first fractional distillation, and another set of passages fulfil another fractional distillation.