A substrate holding mechanism includes: a mounting stage on which a substrate is mounted; a plurality of holding sections each of which includes an upper surface that holds a lower surface of a peripheral section of the substrate and includes a lower surface that pushes down an upper surface of the peripheral section of the substrate mounted on the mounting stage; a protrusion that is provided on the plurality of holding sections and that contacts an end surface of the substrate mounted on the mounting stage to correct a position of the substrate; a lifting and lowering mechanism configured to lift and lower the plurality of holding sections; and a horizontal moving mechanism configured to horizontally move the plurality of holding sections.