In an alerting device for a pager, when a call with a message is received within a predetermined period of time of reception of an initial reception of a call including a message identical to that of the received message, the device conducts an alerting operation to help the user of the pager easily recognize the call. After the predetermined period of time, the device performs an ordinary notification to thereby minimize the current consumption. When a radio section receives a signal including data which matches an address assigned to the pager, a time counter initiates measuring the predetermined period of time and a decoder stores a message obtained from the signal in an RAM. When a next message is received, the decoder compares the received message with the stored one. When "matching" occurs between the messages, the decoder drives a loudspeaker with a large volume or a vibration motor with an increased amplitude when the time counter is measuring the predetermined period of time. After lapse of the predetermined period of time, the decoder drives the loudspeaker with an ordinary volume or a vibration motor with a usual amplitude.