The activity monitor (100) includes a basic information acquisition unit (20) that accepts input of basic physical information (BA) of the user's body, a target information acquisition unit (30) that accepts input of the user's target physical expenditure (CS), an activity pattern acquisition unit (40) that acquires pattern information indicating the user's intent on the activity amount (AM), and a target activity calculation unit (50) that determines a target activity amount (TA) on the basis of the basic physical information (BA), the target physical expenditure (CS), and the pattern information acquired by the activity pattern acquisition unit (40).