An ultrathin electromagnetic vibrating device and its manufacturing method, wherein the ultrathin electromagnetic vibrating device includes: a base frame, a vibrating reed, a set of surrounds, a voice coil and a magnetic circuit system, wherein the surrounds include an upper surround and a lower surround, respectively connected with an upper surface and a lower surface of the vibrating reed to fixedly connecting the vibrating reed with a base of the base frame. Due to an application of the lower surround to form a combined action of the upper and lower surround, the vibrating reed is only able to keep vibrating up and down vertically, a first end of the voice coil is fixedly provided on the lower surface of the vibrating reed, similarly, while a stroke of the voice coil drives the vibrating reed to vibrate up and down vertically, the voice coil achieves an up-and-down vertical stroke.