To provide a method for inspecting a plasma processing device, an inspection device, the plasma processing device, a method for cleaning the plasma processing device, and a method for manufacturing the semiconductor device, in which the condition of a metal attachment inside a transport pipe is sensed.

The inspection method of the plasma processing device includes: a plasma generating chamber which includes a discharge tube and a microwave introduction means and generates plasma by making a microwave act on a gas introduced in the discharge tube; a plasma treatment chamber which accommodates a processed material and can maintain atmosphere which is decompressed less than atmospheric pressure; and a transport pipe which connects the plasma generating chamber and the plasma treatment chamber. The inspection gas is introduced in the discharge tube, and the microwave is introduced in the discharge tube. The plasma of the inspection gas is generated thereby. The light intensity in the plasma treatment chamber is measured.