Precise dew point instrument

The utility model discloses a precise dew-point instrument which comprises a box body, a dew-point instrument body is arranged in the box body, a cover plate is hinged to one side of the top end of the box body, a supporting plate is arranged, when the dew-point instrument body works, the cover plate is opened, and then when a first pull rod, a second pull rod and a third pull rod are used in cooperation, the dew-point instrument body is opened. The connecting plate is driven to move downwards, that is, the supporting legs and the supporting plate are driven to move downwards to support the dew point instrument body, so that the working stability of the dew point instrument body is improved, the use of the dew point instrument body is facilitated, the dew point instrument body is placed inthe box body, and the clamping blocks are clamped with the clamping grooves; and then under the cooperative use of a first spring, a side plate, a first clamping plate, a second spring and a second clamping plate, the dew-po