The present invention relates to a solid oxide fuel cell, which comprises: a plurality of tubular electrodes, reacting gases supplying means, and a preheat piping. The tubular electrodes are concentrically arranged while enabling the polarity of a surface of any one of the plural electrodes is the same as that of the corresponding surface of a neighbor electrode faced thereto; wherein each tubular electrode further comprises an anode layer, a cathode layer, and a solid electrolyte layer sandwiched between the anode layer and the cathode layer. The supplying reacting gases means is capable of supplying fuel and gas respectively to the anode and cathode of the tubular electrodes. The preheat piping, connected to the supplying reacting gases means, collects the heat generated from the combustion reaction of residual fuel and gas, which can be utilized to preheat the gases supplying reacting means. The concentric electrode structure of the invention is compact and space saving, so that the efficiency per unit volume of the fuel cell adopting the same is enhanced. Moreover, by employing the referring fuel cell as one power generating unit, a fuel cell module can be formed by combining a plurality of the power generating units that the modularized design enables the fuel cell module to incorporate any amount of fuel cells therein with flexible formation while enabling each fuel cell of the fuel cell module to be maintained and replaced with ease.