Disclosed are a portable apparatus case, a portable apparatus, and a timepiece allowing easy attachment. A timepiece case includes: a case main body, a first bow having a first passage hole and provided on the case main body, a strap one end portion of which is mounted to the first bow and the other end portion of which is passed through the first passage hole, and a fixation member provided on an extension portion of the strap extending from the first passage hole to the outside and detachably connected to a main portion of the strap extending from the first bow to the first passage hole.