A die bonding device includes: a wafer holder supporting a wafer where a die is formed; an ejector holder disposed at the wafer holder below the wafer and supporting a die ejector that assists separating the die from the wafer; a support unit supporting a substrate where the die is to be attached; a bonding unit that picks up the die from the wafer and attaches the picked-up die to the substrate; an ejector buffer unit that receives the die ejector; and a replacing unit that transfers the die ejector between the ejector holder and the ejector buffer unit.