Abstract: According to a precise critical temperature indicator and a control method thereof of the present invention, the precise critical temperature indicator comprises as one body: a blocking boundary layer which is positioned between a spreading material member including an operation button and spreading medium members including a spreadable area for a spreading material; and a temperature sensor which is controlled and operated as the spreading material passes through the blocking boundary layer and contacts the spreading medium member according to a user's pressing of the operation button. As a result, operation of the temperature sensor is easily controlled using the operation button. Also, the precise critical temperature indicator does not require a process of cooling a product down to below a critical temperature before using the product, due to the hermetic sealing of the spreading material member.

Abstract: A precise critical temperature indicator is applied to small products requiring refrigeration or freezing to control the operation of a temperature sensor built into an integrated structure of a single body. A method for manufacturing said precise critical temperature indicator, wherein a plurality of development medium members and a plurality of development material members are opposed to each other, and blocking members are interposed therebetween to support the development medium members and the development material members separately from each other, the development medium members are provided with paths for moving development materials, or paths for movement of development materials can be shortened to adjust speed, and an indication unit is arranged to indicate the state of the development materials at an end or central portion of the development medium when the development materials are exposed to a critical temperature for a predetermined time period.