A sample holder includes a substrate composed of ceramics, having a sample holding surface provided in an upper face thereof; a supporting member composed of metal, an upper face of the supporting member covering a lower face of the substrate; and a joining layer composed of indium or an indium alloy, the substrate and the supporting member being joined to each other via the joining layer. The joining layer has a layer region in at least one of a joining surface to the substrate and a joining surface to the supporting member, a content percentage of indium oxides of the layer region being higher than that of an intermediate region in a thickness direction of the joining layer.