A slurry for a flexible electrode, consisting of an aqueous emulsion of at least one polymer component selected from the group consisting of acrylic polymers, urethane polymers, fluorine polymers, urea polymers, chloroprene polymers, and butadiene polymers; a component (a) as below, and optionally a component (b) as below, dispersed in the aqueous emulsion; and optionally at least one agent selected from the group consisting of ionic conductive agents, metal particles, conductive polymers, plasticizers, oils, crosslinking agents, anti-aging agents, flame retardants, and coloring agents; wherein the emulsion has a pH of 6.5 to 8.0; in the slurry for a flexible electrode, the total of the at least one polymer component, the component (a) and the component (b) is 20 to 30% by mass; and with respect to the total of the at least one polymer component, the component (a) and the component (b) in the slurry for a flexible electrode, the at least one polymer component is 60 to 85% by mass, and the total of the component (a) and the component (b) is 15 to 40% by mass. Component (a): carbon black having a DBP absorption amount under uncompressed conditions according to JIS K6217-4 of 150 to 300 mL/100 g and a BET specific surface area of 35 to 140 m 2 /g. Component (b): one or more carbons selected from the group consisting of the following α, β, γ, and δ: α: carbon nanotube having a fiber diameter of 1 to 20 nm, β: graphene having a diameter of 0.5 to 10 μm, γ: graphite having a diameter of 0.5 to 10 μm, δ: carbon black having a DBP absorption amount under uncompressed conditions according to JIS K6217-4 of 350 to 500 mL/100 g and a specific surface area of 800 to 1300 m 2 /g. an aqueous emulsion of at least one polymer component selected from the group consisting of acrylic polymers, urethane polymers, fluorine polymers, urea polymers, chloroprene polymers, and butadiene polymers; a component (a) as below, and optionally a component (b) as below, dispersed in the aqueous emulsion; and optionally at least one agent selected from the group consisting of ionic conductive agents, metal particles, conductive polymers, plasticizers, oils, crosslinking agents, anti-aging agents, flame retardants, and coloring agents; the emulsion has a pH of 6.5 to 8.0; in the slurry for a flexible electrode, the total of the at least one polymer component, the component (a) and the component (b) is 20 to 30% by mass; and with respect to the total of the at least one polymer component, the component (a) and the component (b) in the slurry for a flexible electrode, the at least one polymer component is 60 to 85% by mass, and the total of the component (a) and the component (b) is 15 to 40% by mass. Component (a): carbon black having a DBP absorption amount under uncompressed conditions according to JIS K6217-4 of 150 to 300 mL/100 g and a BET specific surface area of 35 to 140 m 2 /g. Component (b): one or more carbons selected from the group consisting of the following α, β, γ, and δ: α: carbon nanotube having a fiber diameter of 1 to 20 nm, β: graphene having a diameter of 0.5 to 10 μm, γ: graphite having a diameter of 0.5 to 10 μm, δ: carbon black having a DBP absorption amount under uncompressed conditions according to JIS K6217-4 of 350 to 500 mL/100 g and a specific surface area of 800 to 1300 m 2 /g. α: carbon nanotube having a fiber diameter of 1 to 20 nm, β: graphene having a diameter of 0.5 to 10 μm, γ: graphite having a diameter of 0.5 to 10 μm, δ: carbon black having a DBP absorption amount under uncompressed conditions according to JIS K6217-4 of 350 to 500 mL/100 g and a specific surface area of 800 to 1300 m 2 /g.