A magnetic stimulation device having planar coil structure is disclosed. It contains a power supply module, a current control module, a plurality of planar coil modules and a plurality of electrical connection modules. In the planar coil module of the present invention, the coil structure has a flat and thin design and can be modularized. Compared with the existing magnetic stimulation devices, the overall structure of the present invention is light, thin, short, convenient to carry and use, and can be installed on clothing or built in a mobile device to provide a convenient magnetic stimulation treatment.