What are the regulations to observe and procedures to follow when importing cosmetics contained in spray cans? 

Regarding importation of cosmetic products, the following regulations apply depending on the form of importation.

(Pharmaceutical Affairs Law, High Pressure Gas Safety Law)

1. Personal Importation
Up to 24 products from an indibidual product category (for instance, any hair spray is counted as hair sprays up to 24 products, regardless of brand or aroma) is allowed for importation as personal items. In such cases, imported cosmetic products cannot be sold or delivered to other persons.

2. Importation as Business
Cosmetic products for import must meet the standards set forth for cosmetics. In addition, procedures for notification of manufacturing/selling, foreign manufacturing/selling, and importation must also be complied with.

3. Cosmetics products contained in spray cans, including hair sprays, shaving foams, and styling spritz in foams, are called "aerosol products". Aerosol products are exempted from regulations on "high-pressure gas" as long as they meet the criteria set out in the High Pressure Gas Safety Law, Enforcement Order of the High Pressure Gas Safety Law, and announcements related to the Order. Therefore, permission of import will be based on simple tests that are different from those applied to other products that are subject to the High Pressure Gas Safety Law.
When clearing customs for import of the product, certification of the tests results meeting the criteria for exemption from the "high-pressure gas" regulations must be attatched as the "document on performance test result". Tests includesize of the container, absence of poisonous activity, and absence of leakage. Labeling is also mandatory.
As an option, you can request Aerosol Industry Association of Japan for import certification tests.