A Geiger-Muller counter tube includes a cylindrical enclosing tube, an anode electrode, a cylindrical cathode electrode, an inert gas, and a quenching gas. The cylindrical enclosing tube has a sealed space. The anode electrode is disposed inside the space and formed in a rod shape. The cylindrical cathode electrode surrounds a peripheral area of the anode electrode inside the space to have an opening. The inert gas and the quenching gas are sealed inside the space. At least one of the anode electrode and the cathode electrode includes a plurality of electrodes inside the enclosing tube.