A side buckle structure of swimming goggles includes a side buckle casing, a press-button seat, a press button, and a head strap. The side buckle casing has a press-button hole, and the press-button seat has a latching hook, a strap hole, placing holes, and elastic devices. Rotating axes, a pressing piece, and a supporting piece are contained in the press button, which is installed on the press-button seat and then inserted into the side buckle casing. According to the aforementioned structure, the side buckle structure is easy to assemble, difficult to dismantle, and very convenient to adjust in usage.