This activation method includes: determining a sequence of activation of plural detection modules each of which is configured to detect a state, for a first condition related to results of detection by the plural detection modules; first activating a detection module that is a first in the sequence; and second activating a certain detection module other than the detection module that is the first in the sequence, upon detecting that a result of detection by a first detection module whose turn in the sequence is immediately before a turn of the certain detection module satisfies a second condition which corresponds to the first detection module and is included in the first condition.