1. Introduction  
2. The SXDS SN Ia Candidates  
2.2. Old Galaxy Selection  
2.3. Selection of the SN Candidates  
3. Measurement of Delay Time Distribution  
4. Examination of Systematic Uncertainties  
5. Implications for the SN Ia Progenitor  
5.1. The Double-Degenerate Scenario  
5.2. The Single-Degenerate Scenario  
6. Conclusions