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 (21, 22) 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 (21, 22), and the plurality of actuators (21, 22) 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 (21, 22) 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 (21, 22), and the plurality of actuators (21, 22) are tightly sandwiched between the arm and the base member by the fastener.