Axis.TickLabelPosition (Excel)
Describes the position of tick-mark labels on the specified axis. Possible return values are xlTickLabelPositionHigh - Top or right side of the chart, xlTickLabelPositionLow - Bottom or left side of the chart, xlTickLabelPositionNextToAxis - Next to axis (where axis is not at either side of the chart), xlTickLabelPositionNone - No tick marks.
XlTickLabelPosition can be one of the XlTickLabelPosition constants.
ActiveChart.Axes(1).TickLabelPosition = xlTickLabelPositionHigh