A maintenance method of a liquid ejection head including a nozzle forming surface where a plurality of nozzles having a polygonal planar shape including a plurality of corners which each have two sides and an angle between the two sides are formed, includes the step of causing a relative movement of a sweep member and the head so as to sweep the nozzle forming surface of the liquid ejection head in such a manner that the sweep member is moved in a direction making an angle within π/8 radian with respect to a direction in which any of the sides extends.