Abstract: Provided is a zeta-potential measurement jig set capable of changing a sample or performing a plating process with a simple operation. The zeta-potential measurement jig set includes a frame and a measurement jig. The frame includes a first and second holding wall, a bottom wall that connects lower ends of the first and second holding wall and includes an anode plate and a cathode plate, and a first lock portion. The measurement jig includes a lower block and disposed on the bottom wall, a cell having a recess in which a sample is disposed and a cell communication hole, a middle block having a frame-like shape surrounding the recess in a plan view, an upper member covering an upper surface of the recess, and a second lock portion pressing the upper member toward the bottom wall. The first lock portion presses the middle block toward the bottom wall.