A cooling structure for cooling semiconductor chips by allowing a cooling fluid to flow and come into contact with the semiconductor chip or a base material with the semiconductor chip disposed thereon, comprising: a vortex-flow generating portion, which extends in a direction intersecting a circulation direction of the cooling fluid, and which generates a vortex flow in accordance with a flow rate of the cooling fluid, wherein the vortex flow is generated by the vortex-flow generating portion in the vicinity of the semiconductor chip or the base material with the semiconductor chip disposed thereon, the vortex-flow generating portion includes a plurality of concave portions arranged at predetermined intervals and a maximum height H of the concave portion is set larger than a thickness δ b of a laminar sublayer in the vicinity of a wall surface, calculated from a Reynolds number Re and a representative length d as fluidization conditions by the following formula: δ b = 63.5/(Re 7/8) × d, W + = Wu τ /v is set within a range of 25 to 300, where W + = Wu τ /v is a value given by nondimensionalizing an opening width W of the concave portion by using a shear rate of u τ = (τ ω /ρ) 1/2 calculated from a shear stress τ ω and a fluid density ρ; an experimental formula of a pipe friction coefficient, represented by C f = τ ω / (0.5ρu 2) = 0.73 Re --0.25 calculated from a flow rate u, a density ρ, and the Reynolds number Re; and a kinetic viscosity v, wherein the representative length d = 4A/L is calculated by a minimum flow passage sectional area A and a maximum wetted perimeter length L of a flow passage section perpendicular to the circulation direction of the cooling fluid, wherein the minimum flow passage sectional area A is a sectional area partitioned by outlines (L1, L2, L3, L4) of the flow passage sectional area A, wherein the wetted perimeter length L is a length of the outline of the section of the flow passage partitioned by the outlines (L5, L6, L7, L8) in contact with the cooling fluid. a vortex-flow generating portion, which extends in a direction intersecting a circulation direction of the cooling fluid, and which generates a vortex flow in accordance with a flow rate of the cooling fluid, wherein the vortex flow is generated by the vortex-flow generating portion in the vicinity of the semiconductor chip or the base material with the semiconductor chip disposed thereon, the vortex-flow generating portion includes a plurality of concave portions arranged at predetermined intervals and a maximum height H of the concave portion is set larger than a thickness δ b of a laminar sublayer in the vicinity of a wall surface, calculated from a Reynolds number Re and a representative length d as fluidization conditions by the following formula: δ b = 63.5/(Re 7/8) × d, W + = Wu τ /v is set within a range of 25 to 300, where W + = Wu τ /v is a value given by nondimensionalizing an opening width W of the concave portion by using a shear rate of u τ = (τ ω /ρ) 1/2 calculated from a shear stress τ ω and a fluid density ρ; an experimental formula of a pipe friction coefficient, represented by C f = τ ω / (0.5ρu 2) = 0.73 Re --0.25 calculated from a flow rate u, a density ρ, and the Reynolds number Re; and a kinetic viscosity v, wherein the representative length d = 4A/L is calculated by a minimum flow passage sectional area A and a maximum wetted perimeter length L of a flow passage section perpendicular to the circulation direction of the cooling fluid, wherein the minimum flow passage sectional area A is a sectional area partitioned by outlines (L1, L2, L3, L4) of the flow passage sectional area A, wherein the wetted perimeter length L is a length of the outline of the section of the flow passage partitioned by the outlines (L5, L6, L7, L8) in contact with the cooling fluid.