Disclosed are an air bubble ingress prevention mechanism, a liquid material discharge device provided with the air bubble ingress prevention mechanism, and a liquid material discharge method, with which a constant filled state can be achieved without variations and without requiring any additional equipment when a metering section is filled with liquid material. A discharge device is provided with a metering section which has a flow passage communicating with a nozzle, and a plunger which moves back and forth within the flow passage of the metering section. The discharge device comprises an air bubble ingress prevention mechanism which can be mounted at the end of the metering section on the opposite side to the nozzle, and which includes: a first hole which communicates with the flow passage of the metering section, and within which the plunger moves back and forth; a first sealing member which is provided at the end of the first hole at the nozzle side; a second sealing member which is provided at the end of the first hole at the opposite side to the nozzle; and a second hole which communicates with the side face of the first hole.