Abstract: An apparatus for modeling a three-dimensional object configured to model a three-dimensional object by a lamination modeling method includes a head for coloring, a head for modeling, a pair of flattening rollers and a main scanning driving unit. The main scanning driving unit is configured to enable at least the head for modeling to perform a main scanning operation in a first direction, which is one side direction of a main scanning direction, and at least the head for coloring to perform the main scanning operation in a second direction, which is the other side direction of the main scanning direction. The one flattening roller of the pair of flattening rollers flattens the three-dimensional object being modeled when the main scanning operation in the first direction is performed, and the other flattening roller flattens the three-dimensional object being modeled when the main scanning operation in the second direction is performed.