In a foam discharge device, a pump has a piston for a liquid linked to a stem, a cylinder for a liquid in which the piston for a liquid is vertically slidably accommodated, a piston for air linked to the stem, a cylinder for air in which the piston for air is vertically slidably accommodated, and an air-liquid mixing unit to mix a liquid from the cylinder for a liquid and air from the cylinder for air to foam the liquid, the cylinder for air is inside a mounting cap and accommodated in a container main body, a head-section-side cylinder for air into which a piston tube erected at a ceiling wall section of the mounting cap is fitted extends from a pressing head, and a communication path to bring the insides of the head-section-side cylinder for air and the cylinder for air in communication is formed at the pump.