A bonding apparatus includes a support including a cavity, and a window fixing chuck facing the support. The support includes a first part including a first through hole extending from the cavity, and a second part extending in a downward direction from the first part and including a second through hole extending from the cavity. A first distance between a first inner surface of the first part and a first outer surface of the first part is less than a second distance between a second inner surface of the second part and a second outer surface of the second part. The first inner surface of the first part and the second inner surface of the second part form the cavity.