An inkjet printing method that performs margin-less printing on a base material, comprising the step of: alternately repeating: an operation of discharging ink from an inkjet head based on a discharge rate that represents a ratio of the number of pixels for actually discharging ink to the number of pixels for an object to be discharged in image data having a size larger than that of the base material while relatively moving the base material and the inkjet head in a main-scanning direction; and an operation of moving the inkjet head in a sub-scanning direction after discharging ink in the main-scanning direction is finished, the method further comprising: generating, by means of image data generating means, image data corresponding to each of divided pitches, based on image data corresponding to each pitch for moving the inkjet head in the sub-scanning direction where the pitch is divided into a plurality of divided pitches, in a manner such that: the image data corresponding to each of the divided pitches includes, along a moving direction in the main-scanning direction, a discharge prohibition section (201a, 202a) for not discharging ink, a discharge section (201c, 202c) for discharging ink, and a gradation discharge section (201b, 202b) between the discharge prohibition section (201a, 202a) and the discharge section (201c, 202c) for discharging ink by raising a discharge rate in gradation to a discharge rate in the discharge section (201c, 202c); and the discharge section (201c, 202c) of each of the divided pitches is superposed for the number of the divided pitches in each pitch to have a discharge rate in each pitch; and by means of controlling means, when margin-less printing is performed based on the image data corresponding to each of the divided pitches, stopping discharging ink in the discharge prohibition section (201a, 202a) and discharging ink in an order of the gradation discharge section (201b, 202b) and the discharge section (201c, 202c) when the inkjet head is moved by moving means (12, 24) along the main-scanning direction from an outside of the base material toward an end of the base material, and thereafter moving the inkjet head for one divided pitch. generating, by means of image data generating means, image data corresponding to each of divided pitches, based on image data corresponding to each pitch for moving the inkjet head in the sub-scanning direction where the pitch is divided into a plurality of divided pitches, in a manner such that: the image data corresponding to each of the divided pitches includes, along a moving direction in the main-scanning direction, a discharge prohibition section (201a, 202a) for not discharging ink, a discharge section (201c, 202c) for discharging ink, and a gradation discharge section (201b, 202b) between the discharge prohibition section (201a, 202a) and the discharge section (201c, 202c) for discharging ink by raising a discharge rate in gradation to a discharge rate in the discharge section (201c, 202c); and the discharge section (201c, 202c) of each of the divided pitches is superposed for the number of the divided pitches in each pitch to have a discharge rate in each pitch; and by means of controlling means, when margin-less printing is performed based on the image data corresponding to each of the divided pitches, stopping discharging ink in the discharge prohibition section (201a, 202a) and discharging ink in an order of the gradation discharge section (201b, 202b) and the discharge section (201c, 202c) when the inkjet head is moved by moving means (12, 24) along the main-scanning direction from an outside of the base material toward an end of the base material, and thereafter moving the inkjet head for one divided pitch.