Machine for the surface processing of products (L) under controlled pressure conditions different than the ambient pressure, comprising • at least one sealed chamber (12, 13), provided with at least one opening (15, 16), that can be closed, for inserting and removing a plurality of products (L) to be processed, • a device (30) for adjusting the pressure inside said at least one chamber (12, 13), • in said at least one chamber (12, 13), a moving device (20) for vertically moving said products (L), so as to accumulate at least two said products on levels arranged over one another, • a horizontal moving device (19) for moving said products (L) from and towards said at least one opening (15, 16) when the products (L) are arranged at the same level of said at least one opening (15, 16) wherein, from an operational viewpoint, a plurality of said products (L) are inserted into said at least one chamber (12, 13), and at least two products of said plurality of products (L) are over one another for a span of processing, and wherein, once all the products to be processed have been inserted into said at least one chamber, (12, 13) said chamber (12, 13) is closed and the pressure inside is adjusted up to an operational processing pressure, and then said at least one chamber (12, 13) is opened again and the products (L) are removed therefrom.