A heat pump mounting box for a heat pump drier or washer-drier, and a heat pump drier or washer-drier having the same are provided. The heat pump mounting box includes a base provided with an air suction port, a two-device mounting chamber, a fan mounting chamber, and a fan air inlet for communicating the two-device mounting chamber and the fan mounting chamber; an air passage guide plate mounted to the base and defining, together with the base, an air guide passage that has a drying air inlet in communication with the air suction port and a drying air outlet in communication with the two-device mounting chamber; an air guide wall disposed in the two-device mounting chamber and opposite the drying air outlet; and a cover plate mounted over the base and at least covering the two-device mounting chamber. The heat pump mounting box according to the present invention has a high utilization rate of the drying air and a good drying performance.