When the distal end of a radiation detection probe (2) is directed toward a place to be measured, pointer light emitted by a light-emitting device (7) sequentially passes through a transmission window (5C) of a radiation detection element (5) and a projection window (3E) of a probe cover (3) to be emitted onto the place to be measured. This pointer light clearly indicates the place as a bright spot. The radiation from the place passes through the distal end of the probe cover (3) to be collimated by a radiation-introducing window (4A) of a side shield (4), and then enters the radiation detection element (5). The dose of the radiation is detected in this way.