A pivot structure includes a base, a bracket, an elastic member and a positioning assembly. The bracket is rotatably connected to the base. The elastic member is disposed on the base. The positioning assembly includes a linkage member and a sleeve. The linkage member is pivoted to the bracket and has a positioning portion. The sleeve is pivoted to the base. The sleeve is fitted around the linkage member and has a releasing segment and a positioning segment. The bracket is adapted to be expanded to a first expanding state relative to the base by the elastic force of the elastic member, so as to drive the positioning portion to move along the releasing segment. The bracket is adapted to receive an external force to be continually expanded to a second expanding state relative to the base, so as to drive the positioning portion to move to the positioning segment.