A conveniently foldable high chair comprises a joint assembly and a front bipod, a rear bipod, a backrest assembly and a dinner plate which are connected with the joint assembly respectively and are mutually rotatable. The joint assembly is provided with a first lock unit for locking the joint assembly to prevent the joint assembly from rotating. A collection belt assembly for driving the first lock unit to be unlocked is disposed on the front bipod and driven to unlock the first lock unit. The front bipod, the rear bipod, the backrest assembly and the dinner plate connected with the joint assembly are folded under the gravity thereof, so that the objective of folding and collection in one second can be achieved. Moreover, after the front bipod, the rear bipod, the backrest assembly and the dinner plate are folded through the joint assembly, the volume is very small.