To provide a resin composition improved in die line in T-die film working, a manufacturing method of a film made by T-die film working of the resin composition under a high temperature, and a film made by the manufacturing method.

This resin composition contains 80-99 wt.% component (A) and 20-1 wt.% component (B) to the total 100 wt.% of the component (A) and the component (B). Component (A) is an ethylene/α-olefin copolymer satisfying condition A-1: melt flow rate is 1-30 g/10 minute, and A-2: molecular weight distribution is 1-3, and component (B) is an ethylene polymer satisfying condition B-1: melt low rate is 0.1-1 g/10 minute, and B-2: the quantity of a component having a specific molecular chain length is 12-50 wt.%.