A wafer holder includes: a frame-shaped holder main body which has an opening at its center and carries a wafer on its upper surface; guide members which contact the outer periphery of the wafer placed on the holder main body and position the wafer on the holder main body; and cross section sample holding members which are disposed on an outer circumference of the holder main body and holds a cross section sample produced from the wafer. Each of the cross section sample holding members includes plate-shaped sample stands to which the cross section sample is fixed, and fixing stands each of which is detachably attached to the holder main body and pinches the sample stand such that the sample stand is attachable to and detachable from the fixing stand.