When automotive heat exchangers such as radiators and condensers are manufactured, serious erosions caused by the molten filler metal from header occasionally occurs on the tubes during brazing. In our previous study, we made a novel experimental method which consisted of using a feeder and a base plate on a gutter made for the flow of molten filler, and we quantitatively evaluated the relationship between the volume of flowing molten filler and the level of erosion. We used Al-12%Si molten filler to investigate the effect of chemical composition, in particular, the Si content of the base plate, on the level of erosion. When Al-0~1.2%Si alloys which have a solidus temperature that is higher than their brazing temperature were used, the level was almost constant irrespective of the Si content of the base metal. However, when an Al-2.0%Si alloy, which has a solidus temperature that is lower than its brazing one, is used, the level increases.