A method for kneading rubber has a first step of preparing a reference rubber composition and measuring a spring property of reference crosslinked rubber obtained by crosslinking the reference rubber composition, a second step of preparing a target rubber composition and measuring a spring property of target crosslinked rubber obtained by crosslinking the target rubber composition, and a third step of comparing the spring property of the target crosslinked rubber with the spring property of the reference crosslinked rubber to set one or more of a compounding condition and a squeezing condition that is adopted in the case of kneading the target lot of the raw rubber in a product composition.