Excel グラフ

[Excel]散布図を作成したとき、それぞれのプロットにラベルを表示したい

Microsoftのサポートに回答がありました。
http://support.microsoft.com/kb/914813/ja

普通に設定する方法はない（≒１つずつ設定しなければならない）ので、VBAを使えと。

   'Dimension variables.
   Dim Counter As Integer, ChartName As String, xVals As String

   ' Disable screen updating while the subroutine is run.
   Application.ScreenUpdating = False

   'Store the formula for the first series in "xVals".
   xVals = ActiveChart.SeriesCollection(1).Formula

   'Extract the range for the data from xVals.
   xVals = Mid(xVals, InStr(InStr(xVals, ","), xVals, _
      Mid(Left(xVals, InStr(xVals, "!") - 1), 9)))
   xVals = Left(xVals, InStr(InStr(xVals, "!"), xVals, ",") - 1)
   Do While Left(xVals, 1) = ","
      xVals = Mid(xVals, 2)
   Loop

   'Attach a label to each data point in the chart.
   For Counter = 1 To Range(xVals).Cells.Count
     ActiveChart.SeriesCollection(1).Points(Counter).HasDataLabel = _
         True
      ActiveChart.SeriesCollection(1).Points(Counter).DataLabel.Text = _
         Range(xVals).Cells(Counter, 1).Offset(0, -1).Value
   Next Counter

を貼りつけて実行すればOK。 なんだかなー。