A cassette type mold apparatus includes a sub-runner formed on a parting surface of a fixed side matrix or a movable side matrix, a gate provided in a fixed side cassette mold or a movable side cassette mold and configured to inject a molten resin into a cavity space from the sub-runner, and a hot runner provided on the fixed side matrix so that a tip end thereof is aligned with the sub-runner to be perpendicular to the sub-runner and is in parallel with a mold opening and closing direction. In the cassette type mold apparatus, the movable side cassette mold can be stacked on the fixed side cassette mold in a state in which a cavity and a core are aligned and can be integrally loaded in a direction of a side surface of the entire mold.