A lap welding method of a steel sheet for overlapping and welding a first steel sheet member (1Y, 10) and a second steel sheet member having a flange portion that is overlapped with the first steel sheet member and a standing wall portion that stands from the flange portion, the standing wall portion of the steel sheet member having an R portion that is connected to the flange portion of the steel sheet member and has a predetermined curvature radius, the method comprising: spot welding in a state in which the flange portion is overlapped with the first steel sheet member, thereby forming a plurality of nuggets between the first steel sheet member and the flange portion, along a longitudinal direction of the flange portion; and after the spot welding, laser welding a region between an R stop of the standing wall portion and the nugget, thereby forming a plurality of weld beads along the longitudinal direction of the flange portion, the R stop being a transition place from the R portion to the flange portion determined by the following: on a surface of the flange portion, a straight line is drawn from an end portion of the flange portion toward the inside of the steel sheet member in a width direction, and furthermore, a perpendicular line is drawn from a point A on the R portion 3 of the steel sheet member so as to intersect the straight line, wherein the point A on the R portion at which a distance d between an intersection point B between the straight line and the perpendicular line and the point A reaches 0.1 mm is considered as the R stop, wherein, the plurality of weld beads is formed at intervals in the longitudinal direction of the flange portion, in the weld bead, a dimension in a longitudinal direction of the flange portion is equal to or longer than a diameter (D n) of the nugget, and a width dimension is 0.5 to 3.0 mm, and an end portion of the weld bead in a width direction of the flange portion which is farthest from the R stop is located further inside than an end portion of the nugget which is closest to the R stop in the width direction. spot welding in a state in which the flange portion is overlapped with the first steel sheet member, thereby forming a plurality of nuggets between the first steel sheet member and the flange portion, along a longitudinal direction of the flange portion; and after the spot welding, laser welding a region between an R stop of the standing wall portion and the nugget, thereby forming a plurality of weld beads along the longitudinal direction of the flange portion, the R stop being a transition place from the R portion to the flange portion determined by the following: on a surface of the flange portion, a straight line is drawn from an end portion of the flange portion toward the inside of the steel sheet member in a width direction, and furthermore, a perpendicular line is drawn from a point A on the R portion 3 of the steel sheet member so as to intersect the straight line, wherein the point A on the R portion at which a distance d between an intersection point B between the straight line and the perpendicular line and the point A reaches 0.1 mm is considered as the R stop, wherein, the plurality of weld beads is formed at intervals in the longitudinal direction of the flange portion, in the weld bead, a dimension in a longitudinal direction of the flange portion is equal to or longer than a diameter (D n) of the nugget, and a width dimension is 0.5 to 3.0 mm, and an end portion of the weld bead in a width direction of the flange portion which is farthest from the R stop is located further inside than an end portion of the nugget which is closest to the R stop in the width direction. on a surface of the flange portion, a straight line is drawn from an end portion of the flange portion toward the inside of the steel sheet member in a width direction, and furthermore, a perpendicular line is drawn from a point A on the R portion 3 of the steel sheet member so as to intersect the straight line, wherein the point A on the R portion at which a distance d between an intersection point B between the straight line and the perpendicular line and the point A reaches 0.1 mm is considered as the R stop, wherein, the plurality of weld beads is formed at intervals in the longitudinal direction of the flange portion, in the weld bead, a dimension in a longitudinal direction of the flange portion is equal to or longer than a diameter (D n) of the nugget, and a width dimension is 0.5 to 3.0 mm, and an end portion of the weld bead in a width direction of the flange portion which is farthest from the R stop is located further inside than an end portion of the nugget which is closest to the R stop in the width direction.