An open-type circular knitting machine for the open and width-variable web production, comprising: - a base; - a knitting head mounted onto the base and comprising: - at least a needle-holding element having at least a plurality of needles (6, 7) arranged around a central axis (X-X); a first active needle (6a, 7a) and a last active needle (6b, 7b, 6b', 7b') of said plurality delimiting between them a dead zone of the needle-holding element without needles and/or without active needles, and an operating zone shaped as an arc of circle and provided with active needles; - control means operatively connected at least to the active needles so as to selectively actuate said active needles in order to produce an open knitted fabric, said open knitted fabric extending longitudinally in a continuous manner between two side edges making up two selvedges of the knitted fabric; wherein the needle-holding element rotates continuously around the central axis (X-X), and suitable devices allow at each revolution to begin thread feeding on the first active needle (6a, 7a) and to interrupt feeding on the last active needle (6b, 7b, 6b', 7b'), during the formation of the knitted fabric, and the machine comprises devices for varying the number of active needles in the operating zone so as to adjust the width of the knitted fabric; characterized by further comprising: at least one cutting device arranged downstream from the needle-holding element and configured for progressively cutting the produced fabric. - a base; - a knitting head mounted onto the base and comprising: - at least a needle-holding element having at least a plurality of needles (6, 7) arranged around a central axis (X-X); a first active needle (6a, 7a) and a last active needle (6b, 7b, 6b', 7b') of said plurality delimiting between them a dead zone of the needle-holding element without needles and/or without active needles, and an operating zone shaped as an arc of circle and provided with active needles; - control means operatively connected at least to the active needles so as to selectively actuate said active needles in order to produce an open knitted fabric, said open knitted fabric extending longitudinally in a continuous manner between two side edges making up two selvedges of the knitted fabric; wherein the needle-holding element rotates continuously around the central axis (X-X), and suitable devices allow at each revolution to begin thread feeding on the first active needle (6a, 7a) and to interrupt feeding on the last active needle (6b, 7b, 6b', 7b'), during the formation of the knitted fabric, and the machine comprises devices for varying the number of active needles in the operating zone so as to adjust the width of the knitted fabric; characterized by further comprising: at least one cutting device arranged downstream from the needle-holding element and configured for progressively cutting the produced fabric. - at least a needle-holding element having at least a plurality of needles (6, 7) arranged around a central axis (X-X); a first active needle (6a, 7a) and a last active needle (6b, 7b, 6b', 7b') of said plurality delimiting between them a dead zone of the needle-holding element without needles and/or without active needles, and an operating zone shaped as an arc of circle and provided with active needles; - control means operatively connected at least to the active needles so as to selectively actuate said active needles in order to produce an open knitted fabric, said open knitted fabric extending longitudinally in a continuous manner between two side edges making up two selvedges of the knitted fabric; wherein the needle-holding element rotates continuously around the central axis (X-X), and suitable devices allow at each revolution to begin thread feeding on the first active needle (6a, 7a) and to interrupt feeding on the last active needle (6b, 7b, 6b', 7b'), during the formation of the knitted fabric, and the machine comprises devices for varying the number of active needles in the operating zone so as to adjust the width of the knitted fabric; characterized by further comprising: at least one cutting device arranged downstream from the needle-holding element and configured for progressively cutting the produced fabric. wherein the needle-holding element rotates continuously around the central axis (X-X), and suitable devices allow at each revolution to begin thread feeding on the first active needle (6a, 7a) and to interrupt feeding on the last active needle (6b, 7b, 6b', 7b'), during the formation of the knitted fabric, and the machine comprises devices for varying the number of active needles in the operating zone so as to adjust the width of the knitted fabric; characterized by further comprising: at least one cutting device arranged downstream from the needle-holding element and configured for progressively cutting the produced fabric.