An electromagnetic sensing apparatus built in a touch screen having at least one soft key is provided, in which a Printed Circuit Board (PCB) has at least one sub-area corresponding to the at least one soft key, a controller has at least one input/output channel and controls electromagnetic sensing of the electromagnetic sensing apparatus, and a loop unit extends from one of the at least one input/output channel, has at least one sub-loop arranged in the at least one sub-area on the PCB, and outputs current induced by an electromagnetic field. Each sub-loop outputs a different output value with respect to the electromagnetic field.