Abstract: A container unit for greening of wall surface and greening method using container unit. The planting container unit has an outer container having an upper-surface and a front-surface opening, an inner container that can be inserted into the front-surface opening of the outer container, and a fixing plate where the inner container is fixed to the outer container. The inner container is capable of housing a planting base, incudes a front-surface opening where a plant body part of the pot plant can be exposed to an outside, and includes an upper-surface opening for housing the planting base and the pot plant. The inner container has, on a front surface having the front-surface opening, a front-surface flange that engages with a wall of the outer container around the front-surface opening. The planting container unit is configured such that the inner container is removably housed inside the outer container.