An electric heater comprising: a substrate; and a plane heating element (100, 200 and 300) formed on one surface of the substrate; wherein the plane heating element (100, 200, 300) includes: a first pattern portion connecting a start point and an end point thereof, a third pattern portion surrounding at least a portion of the first pattern portion and connecting a start point and an end point thereof, and a second pattern portion located between the first pattern portion and the third pattern portion and connecting a start point and an end point thereof, which are located at the innermost side of the second pattern portion, wherein the first pattern portion includes: a plurality of first tracks having an arc shape, spaced apart from each other and having a length increasing from the center to the outside, wherein the third pattern portion includes: a plurality of third tracks having an arc shape, spaced apart from each other on the outside of the first track and having a length increasing from the inside to the outside, and wherein the second pattern portion includes: a plurality of second tracks having an arc shape, spaced apart from each other between the first tracks and the third tracks and having a length increasing from the inside to the outside, wherein a width of the third track is longer than a width of the first track, characterized in that the start point and the end point of the third pattern portion are located at the outermost side of the third pattern portion, wherein the plane heating element (100, 200 and 300 includes): a pair of first electrodes (121 and 122) connected to the start point and the end point of the first pattern portion, a pair of second electrodes (221 and 222) connected to the start point and the end point of the second pattern portion, and a pair of third electrodes (321 and 322) connected to the start point and the end point of the third pattern portion, and wherein the third electrodes (321 and 322) are disposed in a direction opposite to the first and second electrodes. a substrate; and a plane heating element (100, 200 and 300) formed on one surface of the substrate; wherein the plane heating element (100, 200, 300) includes: a first pattern portion connecting a start point and an end point thereof, a third pattern portion surrounding at least a portion of the first pattern portion and connecting a start point and an end point thereof, and a second pattern portion located between the first pattern portion and the third pattern portion and connecting a start point and an end point thereof, which are located at the innermost side of the second pattern portion, a first pattern portion connecting a start point and an end point thereof, a third pattern portion surrounding at least a portion of the first pattern portion and connecting a start point and an end point thereof, and a second pattern portion located between the first pattern portion and the third pattern portion and connecting a start point and an end point thereof, which are located at the innermost side of the second pattern portion, wherein the first pattern portion includes: a plurality of first tracks having an arc shape, spaced apart from each other and having a length increasing from the center to the outside, wherein the third pattern portion includes: a plurality of third tracks having an arc shape, spaced apart from each other on the outside of the first track and having a length increasing from the inside to the outside, and wherein the second pattern portion includes: a plurality of second tracks having an arc shape, spaced apart from each other between the first tracks and the third tracks and having a length increasing from the inside to the outside, wherein a width of the third track is longer than a width of the first track, characterized in that the start point and the end point of the third pattern portion are located at the outermost side of the third pattern portion, wherein the plane heating element (100, 200 and 300 includes): a pair of first electrodes (121 and 122) connected to the start point and the end point of the first pattern portion, a pair of second electrodes (221 and 222) connected to the start point and the end point of the second pattern portion, and a pair of third electrodes (321 and 322) connected to the start point and the end point of the third pattern portion, and a pair of first electrodes (121 and 122) connected to the start point and the end point of the first pattern portion, a pair of second electrodes (221 and 222) connected to the start point and the end point of the second pattern portion, and a pair of third electrodes (321 and 322) connected to the start point and the end point of the third pattern portion, and wherein the third electrodes (321 and 322) are disposed in a direction opposite to the first and second electrodes.