Abstract: A flexible, auxiliary frame mounted on a flexible frame of a pair of eyeglasses is disclosed. The frame includes, at its back, a hole in a center of a bridge, two protrusions having a larger bottom at both sides of the hole, and two slots at endpieces. The auxiliary frame comprises a forward tab at a bridge, two grooves at both sides of the tab, two projections having a larger outer end disposed at endpieces, and a rear pad. The projections are matingly fitted in the slots, the tab is fitted in the hole, and the protrusions are fitted in the grooves respectively. Further, the frame together with the auxiliary frame are adapted to flexibly expand with the fastening of the projections in the slots being maintained in response to the wearer's larger head.