A mini-environment apparatus includes a wafer transportation machine transporting a wafer, a wafer transportation room having the machine and passed by the wafer transported to a processing room, a circulating passage where a gas detoured from the transportation room flows, a blowing means forming a circulating current falling in the transportation room and rising in the passage, a current member arranged in a ceiling part of the transportation room and laminarizing the current and introducing this laminarized current into the transportation room, a particle removal filter arranged in either the ceiling part of the transportation room or the passage, and a chemical filter arranged in the passage detachably and separately from the removal filter. The chemical filter is arranged at a position lower than a lowest position where the wafer may pass through in the transportation room.