A recording condition determining method executed by a recording device performing recording onto a recording medium by a main scanning, in which while moving a recording head provided with a plurality of nozzles in a main scanning direction (D1, D2), dots of a liquid are ejected from the plurality of nozzles onto the recording medium, and a sub scanning, in which the recording medium is transported in a sub scanning direction intersecting the main scanning direction (D1, D2), the method comprising: a patch recording step of recording at least one overlap-processing region (44, 45) onto the recording medium by an overlap-processing in which the main scanning is performed on a partial region of the recording medium in an overlapping manner a plurality of times, the patch recording step further including recording patches (44a-c, 45a-c) at a plurality of different positions in the at least one overlap-processing region (44, 45) in the main scanning direction (D1, D2) by a plurality of types of the overlap-processing under respectively different recording conditions; a selection accepting step of accepting selection of a patch (44a-c, 45a-c) from among a plurality of the recorded patches (44a-c, 45a-c); and a determination step of determining, as the recording condition of the overlap-processing of an actual recording, the recording condition of the overlap-processing associated with the patch (44a-c, 45a-c) selected in the selection accepting step; wherein the at least one overlap-processing region (44, 45) is printed alternatively with at least one non-overlap processing region in the sub scanning direction; each raster line in each overlap-processing region (44, 45) is printed by at least two different nozzles in corresponding different passes (P1, P2), including the sub scanning between; and each raster line in the non-overlap processing region is printed by one nozzle in one pass. a patch recording step of recording at least one overlap-processing region (44, 45) onto the recording medium by an overlap-processing in which the main scanning is performed on a partial region of the recording medium in an overlapping manner a plurality of times, the patch recording step further including recording patches (44a-c, 45a-c) at a plurality of different positions in the at least one overlap-processing region (44, 45) in the main scanning direction (D1, D2) by a plurality of types of the overlap-processing under respectively different recording conditions; a selection accepting step of accepting selection of a patch (44a-c, 45a-c) from among a plurality of the recorded patches (44a-c, 45a-c); and a determination step of determining, as the recording condition of the overlap-processing of an actual recording, the recording condition of the overlap-processing associated with the patch (44a-c, 45a-c) selected in the selection accepting step; wherein the at least one overlap-processing region (44, 45) is printed alternatively with at least one non-overlap processing region in the sub scanning direction; each raster line in each overlap-processing region (44, 45) is printed by at least two different nozzles in corresponding different passes (P1, P2), including the sub scanning between; and each raster line in the non-overlap processing region is printed by one nozzle in one pass.