An electromagnetic induction device with a writing function is disclosed in this present invention. The design of this invention combines an electromagnetic induction device and a writing device in a pen-like device. The electromagnetic induction device can be employed as a pointer device of a tablet. The writing device can be used as an ink pen. Moreover, while writing on paper, the tablet can detect and calculate the coordinates of the writing device and save the coordinates in memory device, such as a RAM. After communicating with the host machine, the monitor can response and display the handwriting trace. Hence, it is very convenient for a user to bring and carry a pen-like device with multiple functions according to this invention.