To provide a conjugate fiber capable of exhibiting characteristics such as heat-retaining property, water-absorbing property, softness, lightweight property, fluffy feeling, and to provide a fibrous structural body containing the fibers.

The conjugate fiber forms a core sheath structure of two kinds of thermoplastic resins in the fiber axial direction, and also has a continuous pore 1 in the fiber axial direction within the core component. The core component 2 is a thermoplastic resin (X), while the sheath component 3 is an ethylene-vinyl alcohol-based polymer resin (Y) having wet-heat bonding property but not having hot-water-dissolvable property and having an ethylene unit content of not less than 15 mol%. The weight ratio of both resins (X)/(Y) is (80/20) to (20/80), and the porosity per fiber cross-sectional area is 5 to 30%. The fibrous structural body containing the fibers is also provided.