A substrate bonding apparatus includes a lower chuck, an upper chuck, an electric actuator on a central portion of the upper chuck, a pressure sensor, and a controller. The lower chuck may support a lower substrate, the upper chuck may face the lower chuck such that a lower surface of the upper chuck faces the upper surface of the lower chuck, and the upper chuck may support an upper substrate. The electric actuator may lower a bonding pin through the upper chuck to apply a pressure to the upper substrate supported on the upper chuck. The pressure sensor may be below the lower substrate supported on the lower chuck. The pressure sensor may sense a lowering pressure applied by the bonding pin to the pressure sensor in real time. The controller may control the lowering pressure applied by the bonding pin.