The invention discloses a manual all-directional cutting sizing device for a steel plate. The sizing device comprises a cutting torch, a movable device and a sliding device. The movable device comprises a rotating disc, the cutting torch is fixed to the upper portion of the rotating disc, and the sliding device is arranged on the lower portion of the movable device. The movable device can rotate by 360 degrees around the center of the rotating disc and also can move front and back on the sliding device in the direction of the cutting torch so as to adjust the cutting position of the cutting torch, so that all-directional cutting of the cutting torch is achieved. Electromagnetic elements are fixed to the bottom of the sliding device and used for fixing the sliding device to the steel plate to be cut. The sizing device is simple in structure, convenient to fix, build and dismantle and easy to operate on site. The sizing device is flexible to use and capable of being repeatedly used in multi-segment assemblies, so that the cost of circulating materials is lowered. The sizing device can rotate by 360 degrees, cut the steel plate according to different shapes and guarantee cutting continuity; meanwhile, the sliding device is firmly fixed to the steel plate to be cut through the electromagnetic elements, and sliding rails of the sliding device can guarantee cutting stability.