A plant cultivation device includes a plurality of boxes, a connection unit, and an end section unit. Each box is provided in an inner space thereof with a cultivation chamber and a light source housing chamber. The plurality of boxes are arranged in a line. The connection unit mutually connects two adjacent boxes. The end section unit is mounted to an end section of a box which is arranged in an end of the line. The end section of the box is unconnected to the connection unit. Each box includes a ventilation opening for ventilating the cultivation chamber, and a ventilation port for air cooling the light source housing chamber. Each of the connection unit and the end section unit includes a first ventilation passage through which air flows into the ventilation opening, and a second ventilation passage through which air flows into the ventilation port.