The present invention relates to an exhaust valve of a diesel engine for a large ship, containing a shall part and an umbrella part that are integrated with each other and made of an Ni—Cr—Al system Ni-base age-precipitated alloy, in which the exhaust valve has a layered structure and hardness of 600 HV or less as a whole, and the layered structure contains a layer formed of an α-Cr phase having a thickness of 150 nm or more that is aged beyond peak mechanical strength.