Provided are a method for washing a hollow fiber membrane module, which can thoroughly and sufficiently eliminate solids attached to the hollow fiber membrane, and a hollow fiber membrane filtration device. The hollow fiber membrane filtration device is provided with a hollow fiber membrane module having: a container 1 having a treated water outlet 5 and a concentrated water outlet 8; a plurality of hollow fiber membranes 2 that are hollow fiber membranes 2 for separating raw water into permeating water and concentrated water and that are disposed in the vertical direction in the container 1; an upper end securing unit 3 disposed in the upper part of the container 1 for securing the upper ends of the hollow fiber membranes 2; a permeating water chamber 7 that is formed on the upper side of the upper end securing unit 3 and to which the inside of each hollow fiber membrane 2 is connected; and a water conveying pipe 4 for supplying raw water to the inside of the container 1. The water conveying pipe 4 extends i
