Is it illegal for private units not to pay social security?

Legal analysis: it is illegal for private units not to pay social security. The employing unit shall, within 30 days from the date of its establishment, apply to the local social insurance agency for social insurance registration with its business license, registration certificate or unit seal. The social insurance agency shall, within fifteen days from the date of receiving the application, examine and issue the social insurance registration certificate. If the employer fails to declare the amount of social insurance premiums that should be paid according to the regulations, the amount that should be paid shall be determined according to 1 10% of the amount paid by the employer last month. After the payer completes the declaration procedures, the social insurance fee collection agency shall make settlement in accordance with the provisions.

Legal basis: Article 84 of the Social Insurance Law of People's Republic of China (PRC), if the employer fails to register for social insurance, the social insurance administrative department shall order it to make corrections within a time limit; If no correction is made within the time limit, the employer shall be fined between one and three times the amount of social insurance premiums payable, and the directly responsible person in charge and other directly responsible personnel shall be fined between 500 yuan and 3,000 yuan.