To provide a door unit for a doorway, which can surely protect privacy inside a door, and which enables the smooth opening and closing of the doorway.

This door unit for the doorway includes a slide sheet which is formed of a windable sheet material and which opens/closes the doorway, and a device for winding the sliding sheet, which is provided above the doorway. Guide covers, which are equipped with insertion openings for both the right and left ends of the slide sheet, are vertically provided at both the right and left side portions of the doorway, respectively; a vertically-elongated guide rail is arranged in the guide cover; movable bodies movable along the guide rail are provided on both the sides of the lower end of the slide sheet, respectively; anti-coming-off portions for preventing both the ends from coming off the insertion openings are formed almost throughout a length-direction length at both the right and left ends, which are inserted into the insertion openings, of the slide sheet; and a vent hole is provided at the lower end of the slide sheet.