A molded article formed of a composition including 100 parts by weight of at least one kind of resin selected from the group consisting of thermoplastic resins and thermosetting resins, and 0.01 parts by weight to 10,000 parts by weight of a silylated polyolefin, which is obtained by a reaction between a silicon-containing compound containing a structural unit represented by Formula (1) and a vinyl group-containing compound having a defined number average molecular weight, a derivative thereof, or a mixture of these, —Si(R1)H—Y1—  (1) wherein R1 and Y1 are defined and with the proviso that the silylated polyolefin is not obtained by a reaction between a silicon-containing compound containing a structural unit represented by Formula (1) and having two or more SH groups per molecule and a compound having 2.0 or more vinyl groups on average per molecule as the vinyl group-containing compound.