A bonding strength measuring device for measuring the bonding strength between a substrate and a molding compound disposed on the substrate is provided. The measuring device includes a heating platform, a heating slide plate, and a fixing bracket. The heating platform has a first heating area and a first replaceable fixture. The substrate is disposed on the first heating area, and the first replaceable fixture is used to fix the substrate and has an opening exposing the molding compound. The heating slide plate has a second heating area and a second replaceable fixture. The second heating area is used to heat the molding compound, and the second replaceable fixture has a cavity for accommodating the molding compound. The fixing bracket is used to fix the heating slide plate above the heating platform.