A fillet welded joint obtained by overlapping a part of two sheets of base material (12, 14) and performing fillet welding, wherein the fillet welded joint comprises the base material (12, 14), weld metal and heat-affected zone, wherein the base material (12, 14) has a tensile strength of 980 MPa or more, a carbon equivalent of 0.36 or more and 0.60 or less, and the tensile strength [MPa] of 1950 times or more of the carbon equivalent [wt%] of the base material (12, 14), wherein the weld metal has an average carbon equivalent of 0.45 or more and 0.65 or less, and higher carbon equivalent of the base material (12, 14), wherein the carbon equivalent of the base material (12, 14) and the weld metal is represented by the following formula: carbon equivalent [wt%] = C + Si / 24 + Mn / 6 + Ni / 40 + Cr / 5 + Mo / 4 + V / 14, wherein C, Mn, Ni, Cr, Mo, and V in the formula are content rates [wt%] in each material, wherein, in a cross section perpendicular to the welding line of the fillet welded joint, on a straight line parallel to the surface of the base material (12, 14), passing a position of 0.1mm or more and 0.3mm or less from the weld toe in the plate thickness direction of the base material (12, 14), a Vickers hardness HVbond at a boundary between the weld metal and the heat affected zone and located below the weld toe, an average value HVwmt of the Vickers hardness of the weld metal in a position of 0.1mm or more and 0.3mm or less from the boundary to the weld metal side, and an average value HVhaz of the Vickers hardness of the heat affected zone in a position of 0.1mm or more and 0.3mm or less from the boundary to the heat affected zone side satisfy the following relationship. HVbond ≤ HVwmt HVbond ≥ HVhaz − 50 and HVhaz ≤ 350 wherein the fillet welded joint comprises the base material (12, 14), weld metal and heat-affected zone, wherein the base material (12, 14) has a tensile strength of 980 MPa or more, a carbon equivalent of 0.36 or more and 0.60 or less, and the tensile strength [MPa] of 1950 times or more of the carbon equivalent [wt%] of the base material (12, 14), wherein the weld metal has an average carbon equivalent of 0.45 or more and 0.65 or less, and higher carbon equivalent of the base material (12, 14), wherein the carbon equivalent of the base material (12, 14) and the weld metal is represented by the following formula: carbon equivalent [wt%] = C + Si / 24 + Mn / 6 + Ni / 40 + Cr / 5 + Mo / 4 + V / 14, wherein C, Mn, Ni, Cr, Mo, and V in the formula are content rates [wt%] in each material, wherein, in a cross section perpendicular to the welding line of the fillet welded joint, on a straight line parallel to the surface of the base material (12, 14), passing a position of 0.1mm or more and 0.3mm or less from the weld toe in the plate thickness direction of the base material (12, 14), a Vickers hardness HVbond at a boundary between the weld metal and the heat affected zone and located below the weld toe, an average value HVwmt of the Vickers hardness of the weld metal in a position of 0.1mm or more and 0.3mm or less from the boundary to the weld metal side, and an average value HVhaz of the Vickers hardness of the heat affected zone in a position of 0.1mm or more and 0.3mm or less from the boundary to the heat affected zone side satisfy the following relationship. HVbond ≤ HVwmt HVbond ≥ HVhaz − 50 and HVhaz ≤ 350