A apparatus for detecting a biological data of a target patient from an attachable sensor attached to the target patient includes a circuit. The circuit obtains the biological data and sensor-state data of the sensor, the biological data and the sensor-state data being collected by the sensor. Further, the circuit evaluates the reliability of the biological data on the basis of a comparison between the sensor-state data and an operation permitting condition for the sensor that is a condition under which a normal operation of the sensor is ensured.
