PURPOSE: To provide a device suited to vaporized injection of fuel in an approximately cylindrical rotary plug for introducing fluid into a combustion chamber for an internal combustion engine.

CONSTITUTION: A plug includes at least an inner channel 1 having a bent part for letting the fluid flow. Each of the channel includes an inlet port 2 located in the cylindrical bottom face of the plug, an outlet port 3 located in the outer circumferential face of the cylinder, and a bend for temporarily holding back the heavier constituents of the fluid under the effect of the centrifugal force with the rotation of the plug, and the wall thickness sandwiched between the outside face of the channel and the outer circumferential face of the plug is relatively thin at the level of the bend. At least one of the outlet ports of at least one of the channels and at least one of the bends are on the same cross-section of the rotary plug.