Modified conjugated diene rubber, method for producing same, and rubber composition

A method comprising:

• reacting a conjugated diene polymer with a hydrocarbyloxysilane compound having one or more functional groups (I) and one or more a functional groups (II) in a molecule thereof to obtain a modified conjugated diene polymer containing the functional group (II), wherein the conjugate diene polymer comprises a structural unit derived from a conjugated diene compound and optionally a structural unit derived from an aromatic vinyl compound, and further comprises an alkali metal or alkaline-earth metal active end, the functional group (I) is a hydrocarbyloxysilyl group, and the functional group (II) is a nitrogen-containing group in which both of two hydrogen atoms of a primary amino group are substituted with a protective group;
• and
• mixing the modified conjugated diene polymer and at least one compound selected from the group consisting of an organic acid, an organic acid halide, and a carboxylic anhydride to obtain a modified conjugated diene rubber.