To provide a word string recognizing method capable of effectively detecting a path of a plausible candidate character from a series of a candidate character even in a state where erroneous recognition or the recognition impossibility exists in large numbers.

This word string recognizing method outputs a plausible word string as a recognizing result by analyzing an input word string having a hierarchy structure based on a word dictionary for correspondingly storing a word and the hierarchy structure, and includes a character recognizing step, a word plausibility calculating step, a word string plausibility calculating step, and a word authorizing step. The word authorizing step first determines respective word plausibility and word string plausibility equivalent to n words by analyzing continuous n words being n≥2 from the forefront of the input word string, authorizes the forefront m candidate word being m<n for constituting a candidate word string of the plausible continuous n words, next analyzes a succeeding word string in succession to the m candidate word in the input word string, and finally determines an authorizing word of the whole hierarchy for constituting the input word string as the recognizing result of the input word string.