To solve the problem of low heat dissipation efficiency of existing electrical control modules an air conditioner is provided that includes an outdoor unit, and the outdoor unit has an air outlet and includes an electrical control box; the electrical control box includes an electrical control module configured with a heat dissipation unit; the heat dissipation unit includes a heat dissipation assembly and a flow guide member enclosing the heat dissipation assembly, the flow guide member and the heat dissipation assembly form an air discharge region close to the air outlet, and the flow guide member and the heat dissipation assembly form an air intake region remote from the air outlet; the air discharge region is smaller than the air intake region. As a result, the velocity of air flowing through the heat dissipation assembly is increased and the heat dissipation efficiency is improved.