To provide a tank integrated centrifugal pump capable of preventing gas lock which is a weak point of the centrifugal pump.

The tank integrated centrifugal pump includes a tank chamber accumulating the liquid flowing in from a flow inlet and the gas mixed in the liquid, a pump chamber provided continuously below the tank chamber and discharging the liquid from an outlet and an impeller installed in the pump chamber and sending the liquid with use of centrifugal force by rotation and is characterized in that it sends the gas to the tank chamber and always fills the pump chamber with the liquid so that the gas lock is not caused.