A fixing device includes a heat applying coil formed by winding a wire around the circumference of a coil supporting member disposed along the inside of the cylindrical fixing roller, for heating the fixing roller by inducing an induced current therein, and a pressing roller which forms a nip portion with the fixing roller, and conveys a transfer material gripped by the nip portion between the fixing roller and the pressing roller, thereby fixing a toner image formed on the transfer material by heat energy given from the fixing roller. The heat applying coil is formed by winding a wire so as to have a shape which has parts parallel to the longitudinal direction of the coil supporting member and parts lying along the circumference of the coil supporting member. The winding density of the latter parts is higher than that of the former parts.