1. A work robot which executes a work to operate a target, the work robot comprising: an image-capturing unit which captures an image including the target; a storage unit which stores, during teaching, an image captured by the image-capturing unit and an operation content taught by an operator in correlation to each other; and a controlling unit which acquires, during work, an image captured by the image-capturing unit, searches the storage unit for an image which is similar to the acquired image, and operates the target based on an operation content correlated to an image found from the storage unit as a result of the search.