An electronic clock makes no erroneous determination of rotation detection and suppresses unnecessary current consumption even when being provided with a second hand having a large moment of inertia. The electronic clock uses a first detection mode determination circuit and a second detection mode determination circuit to perform the rotation detection. The electronic clock includes a determination selecting circuit as changing means for changing the determination period of the second detection mode in accordance with the determination period of the first detection mode. Even when the current waveform is disturbed, erroneous determinations are prevented in a way that the determination terminal of the second detection mode is shortened if the first detection mode terminates earlier. The determination period is changed by the determination selecting circuit selecting either one of a seven-time detection/determination circuit that terminates the determination after seven detection pulses or a six-time detection/determination circuit that terminates the determination after six detection pulses. Alternatively, instead of the number of detection pulses, a cycle of the detection pulses may be shortened.