A fixing device includes a pressing roller, a rotating member, a heating means, a pressing mechanism, a separation member, a first biasing member and a moving mechanism. The pressing roller has a core metal and an elastic layer. The separation member includes a contact part. The first biasing member is configured to bias the separation member to be rotated in a direction in which the contact part is butted against the rotating member. The first biasing member includes a first end portion by which biasing force is acted on the separation member and a second end portion opposite to the first end portion. The moving mechanism is configured to move the second end portion of the first biasing member in a direction in which the biasing force is decreased, as the core metal approaches the rotating member owing to decrease in rigidity of the elastic layer of the pressing roller.