An apparatus configured to measure telescoping of a coil, comprising: a laser generation unit configured to generate at least one laser line output to a lateral surface of the coil and passing through a center of the coil; a camera unit configured to capture an image of the lateral surface of the coil, including the at least one laser line; and a measurement unit configured to measure a degree of telescoping of the coil along a length corresponding to the lateral surface of the coil, among lengths of the at least one laser line, from the image captured by the camera unit; wherein the laser generation unit comprises a first line laser generator, a second line laser generator, and a third line laser generator, configured to respectively output laser lines (b1, b2, b3) to the lateral surface of the coil at equal intervals; wherein the measurement unit is configured to recognize both end points (X 1, X 2, X 3, Y 1, Y 2, Y 3) of the laser line (b 1, b 2, b 3) overlapping an inner circle and an outer circle of the coil, among the laser lines (b 1, b 2, b 3), from the image captured by the camera unit, and to recognize a case in which a length between the both end points (X 1, X 2, X 3, Y 1, Y 2, Y 3) of the laser line (b 1, b 2, b 3) is within a preset range, as the coil; wherein the measurement unit is configured to calculate radii of the inner circle and the outer circle of the coil, wherein the difference between these values indicates the exact length of the telescope in the actual coil, that is, the thickness of the coil, and to correct the measured value of the laser line (b 1, b 2, b 3) obtained by the actual camera to the calculated length. a laser generation unit configured to generate at least one laser line output to a lateral surface of the coil and passing through a center of the coil; a camera unit configured to capture an image of the lateral surface of the coil, including the at least one laser line; and a measurement unit configured to measure a degree of telescoping of the coil along a length corresponding to the lateral surface of the coil, among lengths of the at least one laser line, from the image captured by the camera unit; wherein the laser generation unit comprises a first line laser generator, a second line laser generator, and a third line laser generator, configured to respectively output laser lines (b1, b2, b3) to the lateral surface of the coil at equal intervals; wherein the measurement unit is configured to recognize both end points (X 1, X 2, X 3, Y 1, Y 2, Y 3) of the laser line (b 1, b 2, b 3) overlapping an inner circle and an outer circle of the coil, among the laser lines (b 1, b 2, b 3), from the image captured by the camera unit, and to recognize a case in which a length between the both end points (X 1, X 2, X 3, Y 1, Y 2, Y 3) of the laser line (b 1, b 2, b 3) is within a preset range, as the coil; wherein the measurement unit is configured to calculate radii of the inner circle and the outer circle of the coil, wherein the difference between these values indicates the exact length of the telescope in the actual coil, that is, the thickness of the coil, and to correct the measured value of the laser line (b 1, b 2, b 3) obtained by the actual camera to the calculated length.