A radiation measurement apparatus for measuring radiation includes a first and second Geiger-Muller counter tubes and a radiation-direction calculating unit. The first Geiger-Muller counter tube seals an electrode within a circular pipe-shaped enclosing tube that extends in a straight line. The first Geiger-Muller counter tube is arranged along a first direction. The second Geiger-Muller counter tube seals an electrode within a circular pipe-shaped enclosing tube that extends in a straight line. The second Geiger-Muller counter tube is arranged in a second direction intersecting with the first direction. The radiation-direction calculating unit is configured to compare a first detection signal and a second detection signal with one another to calculate a direction of radiation to be emitted from the sample. The first detection signal is output from the electrode of the first Geiger-Muller counter tube. The second detection signal is output from the electrode of the second Geiger-Muller counter tube.