In order to provide a method of joining a cylinder head 2 and a valve seat 3 by press and heat generated on passing an electrical current through both members 2, 3, to achieve satisfactory joining with minimized heat generated inside when the current is supplied, while eliminating the need for an infiltration step and reduce the production cost, inhibiting an increase in thermal conductivity of the valve seat 3 and improving the wear resistance thereof. The valve seat 3 is made of a sintered material made from a powdery material with a high electrical conductivity element such as Cu dispersed therein. The current and the pressure are applied with a first joining surface 3a of the valve seat 3 and a joining surface 2a of the cylinder head body 2 being put into surface contact with each other in advance.