To provide a laminated membrane cartridge which may be sufficiently and easily washed down to the deep parts between membrane leaves.

The laminated membrane cartridge internally has a supporting body 1 having liquid collecting spaces 1a. The plural membrane leaves 2 having flexibility are erected at specified intervals on the supporting body 1. The membrane leaves 2 are formed to a bag form by sandwiching permeate flow passage members 4 with two separation membranes 3. The opening ends of the respective membrane leaves 2 are communicated with the liquid collecting spaces 1a of the supporting body 1. The base surface of the supporting body 1 is provided with a permeate outlet 6.