According to an embodiment, a work support device includes a measurement unit and an irradiation control unit. The measurement unit measures an in-passage structure of a passage inside of which a user can work. The irradiation control unit controls an irradiation unit to emit light indicative of a work region to a corrected work position obtained by correcting work position information set based on a predetermined designed in-passage structure indicative of an ideal structure in the passage by using a result of the measurement by the measurement unit.