Abstract: First and second detecting wheels, the phases of which can be varied in accordance with the setting of an alarm signaling time, are provided in correspondence to an hour time wheel and a minute time wheel respectively. Among a plurality of leaves adapted for digitally indicating the minute time, some of the leaves, which occur at a constant interval of minutes, are each provided with a projection, and a third detecting means is provided to detect the presence or absence of this projection. An alarm device is actuated when the first and second detecting wheels and third detecting means are concurrently actuated.