The analysis apparatus 10 includes a plasma generation device 11 and an optical analysis device 13. The plasma generation device 11 generates initial plasma by energizing a substance in space to be turned into a plasma state, and maintains the plasma state by irradiating the initial plasma with electromagnetic wave for a predetermined period of time. Then, the optical analysis device 13 analyzes the target substance 15 based on a time integral value of intensity of emission from the target substance 15 in an electromagnetic wave plasma region, which is maintained by the electromagnetic wave.