To provide an electronic clinical thermometer that can protect a probe of the thermometer sufficiently from pollution or the like.

This clinical thermometer has a wrapping film 2 fixed to cover a front housing portion 15 of the thermometer, and a cap member 3 formed of flexible material into hollow frustum structure opened at the tip portion and fitted to the front housing portion 15 of the thermometer 1. The cap member 3 is formed in such wall thickness structure that tip cross section is in a thin piece state and that thickness is gradually increased from the tip to the base end, and is provided with a stopper part swollen radically outward at the outer periphery of an intermediate part from the tip to the base end. Accordingly, even in the case of inserting the tip portion of the thermometer 1 in the hollow of the ear of a patient, the patient does not feel pressure caused by hard material, and the stopper portion of the cap member 3 prevents such an accident that the tip portion enters too deep in the hollow of the ear of a child to damage the ear.