To provide a solder deaerating device or the like for sufficiently removing air bubbles from solder in a molten state.

A vibrator is provided at an upper end and also a spanker pin 32 for imparting ultrasonic vibration in a vertical direction of the vibrator is provided at the lower end of a horn whose position is controlled in the vertical direction. A projection 32a is provided at the tip of the spanker pin 32. The spanker pin 32 is lowered to the solder 101 in the molten state and the projection 32a is once abutted on a sticking surface 100a of the solder 101 (c). By elevating the spanker pin 32, a prescribed gap G is provided between the projection 32a and the sticking surface 100a and, in that state, the ultrasonic vibration is imparted to the spanker pin 32. By vibrating the solder 101 with the spanker pin 32, the air bubbles 102 in the solder 101 is discharged to an outside without mixing new bubbles.