A method for correcting an amount of ejected ink in a line head inkjet printer, which comprises an inkjet head (2, 13) having: a flow path unit in which the plurality of nozzles are formed; a plurality of actuator units having a trapezoidal shape, the actuator units being arranged on the flow path unit so that oblique sides of adjacent actuator units overlap each other when viewed in the conveyance direction; and a plurality of nozzles, which are divided into the blocks (A-I), which include at least one nozzle; the method comprising: measuring the amount of ink ejected from each of n blocks (A-I) divided by n-1 virtual lines extending in a conveyance direction of a printing medium where n represents a natural number equal to or larger than 2; and obtaining a correction factor for each block (A-I) on a basis of the measured amount of ejected ink in each block (A-I), the correction factors making a difference among the blocks (A-I) in an amount of ejected ink per nozzle becoming smaller than that without using the obtained correction factors, wherein the virtual lines each pass through structural change points in the inkjet head (2, 13), where an oblique side of each actuator unit intersects with a short line of each actuator unit, the structural change points extending in a direction perpendicular to the conveyance direction. a flow path unit in which the plurality of nozzles are formed; a plurality of actuator units having a trapezoidal shape, the actuator units being arranged on the flow path unit so that oblique sides of adjacent actuator units overlap each other when viewed in the conveyance direction; and a plurality of nozzles, which are divided into the blocks (A-I), which include at least one nozzle; the method comprising: measuring the amount of ink ejected from each of n blocks (A-I) divided by n-1 virtual lines extending in a conveyance direction of a printing medium where n represents a natural number equal to or larger than 2; and obtaining a correction factor for each block (A-I) on a basis of the measured amount of ejected ink in each block (A-I), the correction factors making a difference among the blocks (A-I) in an amount of ejected ink per nozzle becoming smaller than that without using the obtained correction factors, wherein the virtual lines each pass through structural change points in the inkjet head (2, 13), where an oblique side of each actuator unit intersects with a short line of each actuator unit, the structural change points extending in a direction perpendicular to the conveyance direction. measuring the amount of ink ejected from each of n blocks (A-I) divided by n-1 virtual lines extending in a conveyance direction of a printing medium where n represents a natural number equal to or larger than 2; and obtaining a correction factor for each block (A-I) on a basis of the measured amount of ejected ink in each block (A-I), the correction factors making a difference among the blocks (A-I) in an amount of ejected ink per nozzle becoming smaller than that without using the obtained correction factors, wherein the virtual lines each pass through structural change points in the inkjet head (2, 13), where an oblique side of each actuator unit intersects with a short line of each actuator unit, the structural change points extending in a direction perpendicular to the conveyance direction.