Abstract: The present invention relates to a treatment device using a magnetic field, which includes a coil generating a pulse magnetic field and a cooling unit. The treatment device using a magnetic field in accordance with an embodiment of the present invention includes: a magnetic field generating coil disposed below a contact surface that closely contacts a portion of a body; a cooling unit configured to supply a fluid that cools the magnetic field generating coil; and a duct configured to guide the fluid between the cooling unit and the magnetic field generating coil. Here, the cooling unit is disposed below the magnetic field generating coil and disposed so that an angle between a fluid supply direction from the cooling unit and a central axis of the magnetic field generating coil is equal to or less than the right angle.