A semiconductor light emitting element with a design wavelength of λ, comprising: a photonic crystal periodic structure having two structures with different refractive indices, wherein the photonic crystal periodic structure is provided on a light extraction plane, wherein each of the parameters period a, radius R and height h of the periodic structure is determined by the following consecutive steps of a step of tentatively determining a ratio (R/a) between the period a and the radius R of the structure that are the parameters of the periodic structure; a step of computing refractive indices n 1 and n 2 of the respective structures and computing an average refractive index n av from the refractive indices n 1 and n 2 and the R/a, and substituting the average refractive index n av into a formula of Bragg conditions, thereby obtaining the period a and the radius R for each order m; a step of analyzing a photonic band structure for TM light using a plane wave expansion method that uses the R/a, the wavelength λ, and the dielectric constants ε 1 and ε 2 of the respective structures obtained from the refractive indices n 1 and n 2; a step of determining R/a at which a total photonic band gap, which is the sum of a PBG1 between a first photonic band and a second photonic band for TM light and a PBG2 between a third photonic band and a fourth photonic band for TM light, becomes maximum by repeating analyses while changing the tentatively determined value of R/a; a step of determining light extraction efficiency with respect to light with the wavelength λ by conducting a simulation analysis of the R/a at which the PBG becomes maximum with a FDTD method using as variables a given depth h of the periodic structure and the period a and the radius R that have been individually determined for each order m (2 ≤ m ≤ 4) of the Bragg conditions; and a step of repeating simulations with the FDTD method to determine the order m of the Bragg conditions at which the light extraction efficiency with respect to light with the wavelength λ becomes maximum and determine the depth h and the parameters of the periodic structure: the period a and the radius R corresponding to the order m. a photonic crystal periodic structure having two structures with different refractive indices, wherein the photonic crystal periodic structure is provided on a light extraction plane, wherein each of the parameters period a, radius R and height h of the periodic structure is determined by the following consecutive steps of a step of tentatively determining a ratio (R/a) between the period a and the radius R of the structure that are the parameters of the periodic structure; a step of computing refractive indices n 1 and n 2 of the respective structures and computing an average refractive index n av from the refractive indices n 1 and n 2 and the R/a, and substituting the average refractive index n av into a formula of Bragg conditions, thereby obtaining the period a and the radius R for each order m; a step of analyzing a photonic band structure for TM light using a plane wave expansion method that uses the R/a, the wavelength λ, and the dielectric constants ε 1 and ε 2 of the respective structures obtained from the refractive indices n 1 and n 2; a step of determining R/a at which a total photonic band gap, which is the sum of a PBG1 between a first photonic band and a second photonic band for TM light and a PBG2 between a third photonic band and a fourth photonic band for TM light, becomes maximum by repeating analyses while changing the tentatively determined value of R/a; a step of determining light extraction efficiency with respect to light with the wavelength λ by conducting a simulation analysis of the R/a at which the PBG becomes maximum with a FDTD method using as variables a given depth h of the periodic structure and the period a and the radius R that have been individually determined for each order m (2 ≤ m ≤ 4) of the Bragg conditions; and a step of repeating simulations with the FDTD method to determine the order m of the Bragg conditions at which the light extraction efficiency with respect to light with the wavelength λ becomes maximum and determine the depth h and the parameters of the periodic structure: the period a and the radius R corresponding to the order m.