To improve a representation effect generated by a three-dimensional picture without replacing the whole displayed picture.

A picture display part for a pachinko machine displays the patterns 31 of three-dimensional pictures consisting of polygons. In the state of being ready, the position (coordinates) of a point light source 32 for illuminating the surfaces of the patterns 31 is set at the intermediate position of two stopped patterns 31 and the color of the point light source 32 is set to be red [see (a)]. After this, while holding the position of the source 32 at the intermediate position of the two stopped patterns 31, a parameter for setting the color of the source 32 is varied gradually from red to blue [see (b)]. After this, while holding the color of the source 32 to be blue, the position of the source 32 is moved to a position equivalent to the rear side of the two patterns 31 from the intermediate position of the two patterns 31 [see (c)]. Thus, beautiful picture variation obtained by smoothly varying shadows and colors on the surface of the pattern 31 can be expressed.