A translation device comprises: a memory that stores first dictionary information including a replacement target term in a first language and a translated word in a second language for the replacement target term in association with each other, and second dictionary information including an alternative term instead of the replacement target term; a controller that replaces the replacement target term included in an input sentence with the alternative term to generate a replaced sentence; and a communication interface that outputs the replaced sentence to an external device and acquires a translation result of the replaced sentence in the second language from the external device. The controller detects a specific character string in the translation result of the replaced sentence acquired from the communication interface, and replaces the detected character string with a translated word associated with the replacement target term in the first dictionary information, to generate a translated sentence.