To provide a base for a panel that can improve work efficiency by keeping not-in-use mounting holes plugged with sealing members, and unplugging only the required mounting holes for use in the repeated use of the base for the panel, thereby preventing ready mixed concrete from intruding into the not-in-use mounting holes when placing the ready mixed concrete.

A rear face 4 of a square thin plate 1 is protrusively provided with projecting rail parts 2a-2e, 3 formed in lattice shape, and a plurality of mounting holes 8 are provided penetrating the predetermined positions of the outer peripheral edge part of a front face. Each mounting hole 8 comprises a counterbore hole part 9 having the same depth as the head 20a of a nail 20 to fit the head 20a therein, a funnel-shaped hole part 10 smaller in diameter than the counterbore hole part 9 and gradually reduced in inner diameter toward the rear face 4 side of the base A for the panel, and a cylindrical hole part 11 having an inner diameter equal to the minimum inner diameter of the funnel-shaped hole part 10 and equal to the outer diameter of a body part 20b of the nail 20. The sealing member 12 comprising a disk top part 13 and a conical body part 14 can be detachably fitted into each mounting hole 8.