Aerodynamic characteristics and flow structures in wakes of delta wings with aspect ratios of 1.28〜4.0 have been investigated at angle of attack 0 ° to 90 °. The Reynolds number based on the maximum chord length is 1.3×10^5. The delta wings with λ=1.2〜2.0 indicate mostly similar C_<Lmax> and α_<C_<Lmax>>, whereas those for delta wings with λ=2.4〜4.0 change gradually with an increase in λ, but in the unstalled and full stalled conditions, the aerodynamic characteristics are quite similar independently of λ. In the unstalled region, clear trailing vortices are formed in the wakes and ring-type vortices which correspond to their aspect ratios are formed.