Datasheet for a DU1PU relay?
Almost certainly very similar to this one (except for the contact rating). 



Note that the contacts are present on the quick connects (top of the relay) but one is also brought down to the PCB. If you're switching mains voltage be sure to stay well clear of that one. 

Be sure to double-check this pinout with a multimeter before depending on it. The two pins on the end (the coil) should measure a few hundred ohms, and then contacts should not show continuity (even on high resistance range) to the coil connections. 

Edit: Based on the Japanese datasheet @Respawned found, I'd say the bottom non-coil terminal may not, in fact, be connected to one of the contacts- it appears to show it connected to another support terminal and nothing else, but your relay only appears to have one pin in that area, so it's important to check with a multimeter.