A portable electronic apparatus and a control method for an electronic apparatus that detects the power-generating state of a power generating unit in a power-saving mode and to positively switch to a normal operation mode. The power-generation voltage of a power generating unit is detected in a power-generation-voltage detection process (steps S2 and S12), and the operation mode of a unit to be driven is switched between a normal operation mode and a power-saving mode according to the power-generating state of the power generating unit or according to the manipulation state of manipulation means in an operation-mode control process (steps S3 to S7, and S10 to S15). In a limiter control process (step S8), the operation of a limiter is disabled when the operation mode of the unit to be driven is the power-saving mode. As a result, it is possible in the power-saving mode that the power-generating state of the power generating unit is detected and the operation mode is positively switched to the normal operation mode in the power-generation-voltage detection process. In a limiter-operation disablement release process (step S13), the limiter is again operated after the operation mode is switched to the normal operation mode.