A tool display box includes a main body having a number of spaced resilient retaining plates projecting outward therefrom. A holding space is defined between each two adjacent resilient retaining plates to hold a tool by two mutually facing walls of the two adjacent resilient retaining plates. Each resilient holding plate includes a distal end having a notch defined therein. A retaining member is secured to each resilient holding plate and includes a passage aligned with the notch. A locking member is extended through the notches of the resilient holding plates and the passages of the retaining members for preventing removal of the tool in the holding space.