A timepiece (0200, 0900, 1200) comprising: - a dual-purpose scale (0201, 0901, 1201) for integrally indicating a physical quantity to be controlled using information about obtained target values established for times and for displaying current time using a plurality of time segments; wherein the dual-purpose scale (0201, 0901, 1201) comprises a light-emitting unit (0907, 1009, 1207) using a plurality of multicolored light-emitting components, - a physical quantity information acquisition unit (0202, 0902, 1202) for obtaining information about the physical quantity associated with time; - a physical saving quantity information acquisition unit (0203, 0903, 1203) for obtaining physical saving quantity information indicating the physical quantity to be obtained by the current time within a time segment using information on average physical quantity in the form of an average resulting when target values obtained within given time segments are divided by a time segment length; - a time display unit (0204, 0904, 1204) for displaying the current time on the dual-purpose scale (0201, 0901, 1201) by light emission; - an achieved value information acquisition unit (0205, 0905, 1205) for obtaining information on a quantity achieved up to the current time for the physical quantity controlled within a given time segment; characterized in that the timepiece further comprises - a quantity variance display unit (0206, 0906, 1206) for indicating the variance in quantity resulting when physical saving quantity up to the current time within a predetermined time segment is subtracted from the achieved quantity, such variance being represented by a higher value than the value for the current time when the variance is of a positive nature, and being represented by a lower value than the value for the current time when the variance is of a negative nature, under the condition that the variance is reckoned from the value for the current time shown on the dual-purpose scale, and a light-emitting control unit for controlling the light-emitting unit such that a scale area representing the higher value than the value for the current time and a scale area representing the lower value than the value for the current time become luminous in different predetermined colors. - a dual-purpose scale (0201, 0901, 1201) for integrally indicating a physical quantity to be controlled using information about obtained target values established for times and for displaying current time using a plurality of time segments; wherein the dual-purpose scale (0201, 0901, 1201) comprises a light-emitting unit (0907, 1009, 1207) using a plurality of multicolored light-emitting components, - a physical quantity information acquisition unit (0202, 0902, 1202) for obtaining information about the physical quantity associated with time; - a physical saving quantity information acquisition unit (0203, 0903, 1203) for obtaining physical saving quantity information indicating the physical quantity to be obtained by the current time within a time segment using information on average physical quantity in the form of an average resulting when target values obtained within given time segments are divided by a time segment length; - a time display unit (0204, 0904, 1204) for displaying the current time on the dual-purpose scale (0201, 0901, 1201) by light emission; - an achieved value information acquisition unit (0205, 0905, 1205) for obtaining information on a quantity achieved up to the current time for the physical quantity controlled within a given time segment; - a quantity variance display unit (0206, 0906, 1206) for indicating the variance in quantity resulting when physical saving quantity up to the current time within a predetermined time segment is subtracted from the achieved quantity, such variance being represented by a higher value than the value for the current time when the variance is of a positive nature, and being represented by a lower value than the value for the current time when the variance is of a negative nature, under the condition that the variance is reckoned from the value for the current time shown on the dual-purpose scale, and