A welding material, comprising a modified polyethylene resin composition (Z) comprising from 0.5 to 95 wt % of a modified polyethylene resin (X) having at least one monomer selected from the group consisting of an unsaturated carboxylic acid and its derivative, grafted to a polyethylene resin (A) having a density of from 0.910 to 0.965 g/cm3 and a MFR (temperature: 190° C., load: 2.16 kg) of from 0.1 to 5.0 g/10 min, and from 5 to 99.5 wt % of an unmodified polyethylene resin (Y) having a density of from 0.930 to 0.965 g/cm3, a MFR of from 0.01 to 5.0 g/10 min and a melt flow rate ratio (HL-MFR (temperature: 190° C., load: 21.6 kg)/MFR of from 40 to 270, and having a density of from 0.938 to 0.965 g/cm3 and a MFR of from 0.05 to 1.0 g/10 min.