Processing apparatus

A conveying unit of a processing apparatus includes a clamping section that clamps a workpiece, and a conveying arm that enables the clamping section to be moved in a height direction and in directions of advancing toward and retracting away from a cassette. The clamping section includes a support section that supports a lower surface of the workpiece, a presser section that makes contact with an upper surface of the workpiece and clamps the workpiece between itself and the support section, and a driving unit that relatively moves the support section and the presser section away from and toward each other. The conveying unit further includes a light reflection type sensor that irradiates the workpiece accommodated in the cassette with light, the light reflection type sensor being fixed to the clamping section and being disposed at a same height as a height when the clamping section clamps the workpiece.