PURPOSE: To sorting with a medicinal effect component-containing granule within a short time by using a placebo granule containing a specific ratio of an iron powder with respect to the whole system.

CONSTITUTION: When the content of the iron powder in a placebo granule is 0.1wt.% or less, sorting recovery due to a magnet becomes low and, when 5wt.% or more, the apparent density of the placebo e granule becomes large and the placebo granule is largely different from a medicinal effect component- containing granaule and correct coating evaluation becomes impossible. Therefore, 0.1-5wt.% of the iron powder is added to the whole system. Lactose, starch, a binder, a disintegrator and the iron powder are charged in a kneader by predetermined amts. to be stirred and a predetermined amt. of water is added to the kneader to be kneaded along with those components. The kneaded mixture is supplied to a granulator to be granulated and dried by a fluidized bed dryer to obtain the placebo granule. This granaule and a main medicine- containing granule are mixed in a proper ratio to perform coating. By this method, the placebo granaule can be attracted and removed by a magnet after coating and workability can be enhanced.