Abstract: A buckle of synthetic resin is composed of a male member and a female member which can be separated from each other and coupled to each other. The male member has an attachment for attachment to a belt or the like, and a connecting portion composed of a central base including a pair of resilient engagement portions having slanted outer surfaces from which grips extend outwardly. The female member includes an attachment and a tubular member in which the central base can be inserted. The tubular member has fingers lockingly engageable with end surfaces of the engagment portions. The engagement portions have teeth disposed respectively on the end surfaces thereof. The central base has stop pawls disposed outwardly of the teeth and extending toward the end surfaces beyond ends of the teeth.