A method for controlling a spin-drying operation of a washing apparatus includes a laundry dispersing step of dispersing the laundry inside a drum by accelerating the drum, a spin-drying step including detecting the eccentricity of the drum, and performing spin-drying by rotating the drum to a spin-drying RPM. The laundry dispersing step is re-executed when the eccentricity exceeds a reference eccentricity, and in the spin-drying step, a rotation time during which the drum rotates at the spin-drying RPM is adjusted according to a spin-drying degree. The spin-drying degree is measured after a point in time at which the eccentricity exceeds the reference eccentricity.