PURPOSE: To emit an electrical signal when the residual amt. of the medicinal liquid used in an instillation container verges to an end and to make it possible to inform a person in charge of medical treatment of this electrical signal in application of an instillation injection for medical treatment.

CONSTITUTION: A transmission means 3 has a shaft end face 28, a shaft 12 upper part 4, an external screw part 12, a shaft lower part 5, a notched shaft bottom end 7. A press spring 40, an A nut 13 and a B nut 10 are inserted to an upper plain bearing 2 from a lower plain bearing 26 of a bearing 2. The A nut 13 is screwed onto the external screw part 12 of the transmission means 3 so as to meet the set residual amt. of the medicinal liquid 19. A terminal hole 20 of a hanging terminal 18 is inserted onto the shaft bottom end 7 of the transmission means 3 and an S-shaped ring 14 is mounted at the hanging terminal 18 to hang the instillation container 15. Further, a hanging hole 29, a microswitch 21, an electric energy source 30, an electric signal device 27 and a wiring 23 are built on a substrate 1 of the device.