A portable electronic apparatus capable of reliably determining whether a load detected by detecting units is caused by water pressure or by some other pressure and performing predetermined control according to the determination. A portable telephone apparatus is provided with operation detecting units and a control unit. The operation detecting units are detecting units for detecting pressure caused by a pressing operation. When a pressure is detected by at least one of the operation detecting units, the control unit performs first control (for example, control caused by detection of pressure other than water pressure). When even pressures are simultaneously detected by the operation detecting units, the control unit performs second control (for example, control caused by detection of water pressure) different from the first control.