This study was performed to design and to construct a digital soil cone index(CI) measuring device replacing conventional analog type devices. The device developed in the study consisted of a load cell, a rotary encoder and a motor with a decelerator as its main parts. The cone speed was controlled lower than 3.0 m/s which keeps the standard suggested by the ASABE S313.3 specification. The experiment was conducted in a soil bin system as well as in various fields. The CI data measured by the developed device were compared with those by an existing measurement device(SC900, Spectrum, USA). Based on the experiments at various field conditions, the CI measuring characteristic of the device was quite similar to that of the conventional device within a acceptable $R^2$ range of more than 0.5(mean=0.76). It was concluded that the digital cone index measuring device was an effective and comprehensive sensor for measuring soil strength.