Method for producing rubber wet masterbatch and method for producing rubber composition

A method for producing a rubber wet masterbatch, the method comprising:

• a step (I) of mixing a rubber latex solution and a part of a coagulant with a carbon black-containing slurry aqueous solution in which a carbon black is dispersed in water, while the rubber latex solution and the part of the coagulant are added to the carbon black-containing slurry aqueous solution, to produce a carbon black-containing rubber latex aqueous solution having a pH of 7 or more and 8.5 or less;
• a step (II) of adding a remaining part of the coagulant to the carbon black-containing rubber latex aqueous solution obtained to produce a carbon black-containing rubber coagulum;
• and
• a step (III) of dehydrating and drying the carbon black-containing rubber coagulum obtained to produce a rubber wet masterbatch,
• wherein in the step (I), a rubber component contained in the rubber latex solution is added at an addition rate of 10 g/min or more and 100 g/min or less and the part of the coagulant is added at an addition rate of 10 mmol/min or more and 100 mmol/min or less per 100 g of the carbon black contained in the carbon black-containing slurry aqueous solution.