An infusion alarm is disclosed, comprising a power supply, a probe, an electric
magnet, a spring, an armature, a contact block and an
electric bell, the power supply, the probe and the electric
magnet are interconnected in series via a lead wire to form a circuit I, the power supply, the spring, the armature, the contact block and the
electric bell are interconnected in series via the lead wire to form a circuit II. As the above structure is used, when used, the probe is inserted into the liquid in an infusion
bottle to switch on the circuit I, the current generated by the electric
magnet moves the armature in the circuit II away from the contact block so that the circuit II can be switched off, and when no liquid is present in the infusion
bottle, the circuit I is switched off, the armature in the circuit II is connected with the contact block under the action of the spring to switch on the circuit II, and the
electric bell makes warning sound to notice patient of the ending of the infusion, thus achieving the purpose of guaranteeing safety of the infusion.