A stroller utilizes a handle folding assembly and a front frame folding assembly for a compact, easy storing folded size. An axle of the handle folding assembly rotates when a wrench is operated with single hand and two first sliders are brought to approach axially to each other and detach from two fastening elements, making the handle rotatable and folding to a rear frame. A button of the front frame folding assembly is pressed with single hand (or a seat is detached from a seat bracket) to detach a second slider of the front frame from a roller to make the front frame rotatable and folding to the rear frame. The position pins accompanied with a plurality of position holes enable the stroller an adjustable height of a seat and the handle.