A fixing device includes: a fixing belt member configured to be endless and rotatable; driving force transmission members that are disposed on respective ends of the fixing belt member, and transmits a rotational driving force to the fixing belt member; and a pressing member that is disposed to push an outer surface of the fixing belt member and forms a fixing nip part between the pressing member and the fixing belt member, wherein each of the driving force transmission members is fixed to the fixing belt member over an entire peripheral area of the corresponding end of the fixing belt member.