An information processing apparatus includes a sensor for generating a sensor output signal responsive to the three-dimensional coordinate position of a detection target in a monitor space by detecting a capacitance in the monitor space, and outputting the sensor output signal, a position detector for detecting the three-dimensional coordinate position of the detection target in the monitor space from the sensor output signal of the sensor, a storage unit for storing coordinate information identifying a three-dimensional space region set in the monitor space, a determining unit for determining whether the three-dimensional coordinate position of the detection target in the monitor space is contained in the three-dimensional set space region, based on the three-dimensional coordinate position of the detection target detected by the position detector and the coordinate information stored on the storage, and an output unit for outputting determination results of the determining unit.