AutoScaleFont Property
True if the text in the object changes font size when the object size changes. The default value is True. Read/write Variant.
Example
This example adds a title to embedded chart one on the active worksheet, and it causes the title font to remain the same size whenever the chart size changes.
With ActiveSheet.ChartObjects(1).Chart
.HasTitle = True
.ChartTitle.Text = "1996 sales"
.ChartTitle.AutoScaleFont = False
End With