An analyzer capable of having a pressure value converge to a set vacuum value P in a short time is provided. An analyzer includes a sample chamber in which a sample is placed, an analysis chamber including an X-ray tube and a detector, a gate valve switching between a connecting state where the inside of the sample chamber and the inside of the analysis chamber are connected together and a disconnecting state where the insides of the chambers and are disconnected from each other, a vacuum pump and a pressure regulatory valve connected to the inside of the sample chamber and the inside of the analysis chamber, and a control unit controlling the degree of opening of the pressure regulatory valve to set the internal pressure of the sample chamber and the internal pressure of the analysis chamber at respective set pressure values in the connecting state.