1. A command recognition device comprising: an utterance understanding unit that determines or selects word sequence information from speech information; speech confidence degree calculating unit that calculates degree of speech confidence based on the speech information and the word sequence information; and a phrase confidence degree calculating unit that calculates a degree of phrase confidence based on image information and phrase information included in the word sequence information, wherein the command recognition device is configured to determine whether a command of the word sequence information is to be executed based on the degree of speech confidence and the degree of phrase confidence.