The present invention provides a tone detector that is capable of performing accurate tone signal detection in a short period of time. Specifically, the tone detector according to the present invention includes: a control unit that measures the tone signals using a plurality of channels having a predetermined measuring time interval, which are shifted by a fixed time period, and reads out the tone signals stored in a memory unit for each of the measuring time intervals; detection processing units that determine the characteristic quantity of the tone signals read out by the control unit; and a tone determination unit that identifies the tone signal for each of the plurality of channels based on the characteristic quantity determined in the detection processing units. In this tone detector, the tone signals are measured using a plurality of channels wherein the measuring time interval of each channel is shifted by a fixed time period after which the tone signal is identified. Thus, the detection result can be obtained after every predetermined time period for each of the shifted channels thereby realizing the tone detection at short time intervals while still maintaining the required measuring time for the tone signal detection.