This apparatus includes a unit for adhering an elastic seal to a lens holder, a unit for causing the lens holder, to which the elastic seal is adhered, to hold a lens, a pivotal arm, an arm driving unit for pivoting the pivotal arm, a clamp unit attached to the pivotal arm to be vertically movable to hold the lens holder, and a clamp driving unit for vertically moving the clamp unit. The pivotal arm is pivoted to sequentially adhere the elastic seal to the lens holder and hold the lens by the lens holder.