The invention provides a pressure-balanced type portable device for soil gas collection. The pressure-balanced type portable device comprises a gas collection box and a gas extraction device, wherein the gas collection box mainly comprises a top cover, a collection box and a base; a first piston is arranged in the top cover; and the base comprises an upper part and a lower part which are provided with an adjustable included angle. During a gas collection process, the internal pressure and the external pressure of the collection box are balanced via the up-and-down movement of the first piston, thus reducing the influence of the pressure change in the collection box on the emission of soil gas, ensuring observation accuracy, and shortening observation time; and particularly, the pressure-balanced type portable device is small in sampling area and good in sealing performance. The pressure-balanced type portable device disclosed by the invention can also be applied to a slope environment with a certain angle by designing the base to be an upper base and a lower base which have an adjustable angle. Additionally, the pressure-balanced type portable device disclosed by the invention also has the advantages of being convenient in getting materials, easy to detach and carry, simple to operate, etc.