A liquid material ejection device comprising: a liquid chamber communicating with an ejection port and being supplied with a liquid material; a plunger including a tip portion that has a smaller diameter than the liquid chamber and is moved back and forth in the liquid chamber ; an elastic member urging the plunger upward; a guide supporting the plunger movably in a vertical direction, an arm disposed in a state extending in a substantially horizontal direction; an arm driver serving as a driving source to operate the arm ; a base member on which the arm driver is disposed, and a rocking mechanism unit connected to the arm driver and rockingly supporting the arm , wherein the arm driver includes a plurality of actuators disposed in a longitudinal direction of the arm , the arm includes a pressing portion pressing the plunger downward, and the plunger is linearly reciprocable with a rocking motion of the arm characterized in that the plunger includes a contact portion being not coupled to the pressing portion and pressed by the pressing portion , the elastic member is a compressed coil spring urging the plunger upward at all times, the plunger is detachably inserted through the elastic member and the guide , and the pressing portion or the contact portion has a curved surface allowing a contact state between the pressing portion and the contact portion to be maintained following the rocking motion of the arm , in that the liquid material ejection device further comprising a fastener detachably supporting the arm to the base member , and the fastener is disposed between the plurality of actuators , and the plurality of actuators are tightly sandwiched between the arm and the base member by the fastener . a liquid chamber communicating with an ejection port and being supplied with a liquid material; a plunger including a tip portion that has a smaller diameter than the liquid chamber and is moved back and forth in the liquid chamber ; an elastic member urging the plunger upward; a guide supporting the plunger movably in a vertical direction, an arm disposed in a state extending in a substantially horizontal direction; an arm driver serving as a driving source to operate the arm ; a base member on which the arm driver is disposed, and a rocking mechanism unit connected to the arm driver and rockingly supporting the arm , wherein the arm driver includes a plurality of actuators disposed in a longitudinal direction of the arm , the arm includes a pressing portion pressing the plunger downward, and the plunger is linearly reciprocable with a rocking motion of the arm characterized in that the plunger includes a contact portion being not coupled to the pressing portion and pressed by the pressing portion , the elastic member is a compressed coil spring urging the plunger upward at all times, the plunger is detachably inserted through the elastic member and the guide , and the pressing portion or the contact portion has a curved surface allowing a contact state between the pressing portion and the contact portion to be maintained following the rocking motion of the arm , in that the liquid material ejection device further comprising a fastener detachably supporting the arm to the base member , and the fastener is disposed between the plurality of actuators , and the plurality of actuators are tightly sandwiched between the arm and the base member by the fastener . <EOS>