Abstract: A protective sheath device includes a housing member having a chamber formed by an erected side panel, an upper panel, a bottom panel, and a tilted side panel having a bottom portion extended toward the bottom panel for forming a slot between the tilted side panel and the bottom panel, a blade member engaged into the chamber of the housing member and having a handle, the housing member includes a rearwardly extended knob located above the handle and having a relatively thinner front portion and a relatively thicker rear portion, and having a planer surface formed in the knob for being engaged with and pushed by a thumb of the user to separate the housing member from the blade member.

Abstract: A knife case is integrally molded to have a shape matching the blade of a knife, and includes a front end, a rear end, an upper edge, a lower edge, and two lateral sides. A rearward opened blade receiving space is defined on the knife case to extend from the rear end toward the front end, a thumb push is provided on the upper edge to project from the rear end, and a through hole is provided on the thumb push for a fastening strap to extend therethrough. With the knife case having the above structure, the knife received therein can be safely displayed for sale without the need of extra packaging material and a user can conveniently and safely remove the knife from the knife case for use.