A plasma emitting device comprising: a nozzle (30, 30') and a plasma head (14, 14') configured to generate a plasmarized gas and jet the plasmarized gas from the nozzle (30, 30'); a gas supply device configured to supply a gas to the plasma head (14, 14') and comprising a mass flow controller configured to control the flow rate of the gas supplied to the gas supply device; a gas tube configured to connect the gas supply device and the plasma head (14, 14') to constitute a flow path for the gas; and a pressure detector configured to detect a pressure of a gas supplied from the gas supply device, and a clogging determination device configured to determine a head clogging impeding a gas flow in the plasma head (14, 14') based on a gas pressure detected by the pressure detector characterized in that: the clogging determination device is configured to obtain - the flow rate of the gas controlled by the mass flow controller; - the length of the gas tube; - the type (Ty) of the plasma head attached to the tube; and is also configured to obtain when a plasma treatment is actually being performed - a reference tube pressure loss (ΔPTA0); - a reference plasma head pressure loss (ΔPHM0); wherein the reference tube pressure loss (ΔPTA0) is set based on the length of the gas tube and the flow rate of the gas controlled by the mass flow controller; and the reference head pressure loss (ΔPHM0, ΔPHH0) is set based on the type of the plasma head (14, 14') and the flow rate of a gas controlled by the mass flow controller flowing through the plasma head (14, 14'); wherein the clogging determination device is configured to set a reference pressure which is a gas pressure to be detected by the pressure detector based on said reference tube pressure loss (ΔPTA0) and on said reference plasma head pressure loss (ΔPHM0) and to then determine on head clogging based on a difference between an actual pressure which is a gas pressure detected actually by the pressure detector and the reference pressure. a nozzle (30, 30') and a plasma head (14, 14') configured to generate a plasmarized gas and jet the plasmarized gas from the nozzle (30, 30'); a gas supply device configured to supply a gas to the plasma head (14, 14') and comprising a mass flow controller configured to control the flow rate of the gas supplied to the gas supply device; a gas tube configured to connect the gas supply device and the plasma head (14, 14') to constitute a flow path for the gas; and a pressure detector configured to detect a pressure of a gas supplied from the gas supply device, and a clogging determination device configured to determine a head clogging impeding a gas flow in the plasma head (14, 14') based on a gas pressure detected by the pressure detector characterized in that: the clogging determination device is configured to obtain - the flow rate of the gas controlled by the mass flow controller; - the length of the gas tube; - the type (Ty) of the plasma head attached to the tube; and is also configured to obtain when a plasma treatment is actually being performed - a reference tube pressure loss (ΔPTA0); - a reference plasma head pressure loss (ΔPHM0); wherein the reference tube pressure loss (ΔPTA0) is set based on the length of the gas tube and the flow rate of the gas controlled by the mass flow controller; and the reference head pressure loss (ΔPHM0, ΔPHH0) is set based on the type of the plasma head (14, 14') and the flow rate of a gas controlled by the mass flow controller flowing through the plasma head (14, 14'); wherein the clogging determination device is configured to set a reference pressure which is a gas pressure to be detected by the pressure detector based on said reference tube pressure loss (ΔPTA0) and on said reference plasma head pressure loss (ΔPHM0) and to then determine on head clogging based on a difference between an actual pressure which is a gas pressure detected actually by the pressure detector and the reference pressure. the clogging determination device is configured to obtain - the flow rate of the gas controlled by the mass flow controller; - the length of the gas tube; - the type (Ty) of the plasma head attached to the tube; and - the flow rate of the gas controlled by the mass flow controller; - the length of the gas tube; - the type (Ty) of the plasma head attached to the tube; and is also configured to obtain when a plasma treatment is actually being performed - a reference tube pressure loss (ΔPTA0); - a reference plasma head pressure loss (ΔPHM0); wherein - a reference tube pressure loss (ΔPTA0); - a reference plasma head pressure loss (ΔPHM0); wherein the reference tube pressure loss (ΔPTA0) is set based on the length of the gas tube and the flow rate of the gas controlled by the mass flow controller; and the reference head pressure loss (ΔPHM0, ΔPHH0) is set based on the type of the plasma head (14, 14') and the flow rate of a gas controlled by the mass flow controller flowing through the plasma head (14, 14'); wherein the clogging determination device is configured to set a reference pressure which is a gas pressure to be detected by the pressure detector based on said reference tube pressure loss (ΔPTA0) and on said reference plasma head pressure loss (ΔPHM0) and to then determine on head clogging based on a difference between an actual pressure which is a gas pressure detected actually by the pressure detector and the reference pressure.