A support base supports a plate-shaped workpiece. The support base includes a flat plate-shaped box member having a support face for supporting a workpiece and a placement face that is a face on the opposite side to the support face and is placed on a holding face of a chuck table, a temperature measurement unit accommodated in the box member, and a battery accommodated in the box member and serving as a power supply for the temperature measurement unit. The temperature measurement unit includes a temperature measuring instrument that measures a temperature at the support face, and a recording unit that records the temperature measured by the temperature measuring instrument.