How Classification Works
Japan uses a four-class system (I–IV) structured around intended use and risk, administered through the PMD Act and Cabinet Order. Classification determines not just the regulatory pathway but also which QMS Ordinance requirements apply and what post-market surveillance obligations attach. The system uses JMDN codes as the primary classification tool.
The four-class system
Japan classifies medical devices into four classes based on the potential risk to patients:
| Class | Name | Risk level | Pathway | Examples |
|---|---|---|---|---|
| Class I | General medical devices (一般医療機器) | Lowest | Todokede | Bandages, tongue depressors, examination gloves |
| Class II | Controlled medical devices (管理医療機器) | Moderate | Ninsho (usually) | X-ray film, hearing aids, contact lenses |
| Class III | Specially controlled medical devices (高度管理医療機器) | High | Shonin (usually) | Dialysis equipment, orthopedic implants, ventilators |
| Class IV | Specially controlled medical devices (高度管理医療機器) | Highest | Shonin only | Cardiac stents, pacemakers, HIV IVDs |
Note that Class III and Class IV are both categorised as "Specially Controlled Medical Devices" (高度管理医療機器) in the PMD Act. The distinction between Class III and IV is made in the Cabinet Order and affects which devices can use Ninsho vs Shonin.
How JMDN drives classification
Rather than relying on a risk-based algorithm applied case by case (as in the EU IVDR rule system), Japan's classification is primarily done by looking up the JMDN code for the device type. JMDN codes have pre-assigned classes. If a device type exists in the JMDN database with a Class II designation, that device is Class II.
This means the critical first step is identifying the correct JMDN code. For devices with existing JMDN codes, the class is straightforward to determine. For novel devices with no existing JMDN code, a new code must be created through an MHLW process — which takes time and may require a PMDA consultation.
Who makes the classification decision
For most devices, classification is determined by the MAH or applicant by looking up the JMDN code. There is no formal pre-application classification determination process for standard devices.
For novel or borderline devices where no JMDN code exists or where the intended use is genuinely ambiguous, the MAH should seek a PMDA consultation (for Shonin-track devices) or engage MHLW directly. MHLW has authority to create new JMDN codes and assign classes.
Reclassification
MHLW can reclassify device categories — moving a device type from one class to another — through amendment of the Cabinet Order. This has happened for certain IVD categories and some SaMD types as new evidence emerged. Reclassification affects existing approvals and certifications, and MAHs are required to transition to the new pathway within MHLW-specified timeframes.