Coolant supply device and electric drill unit provided with coolant supply device

A coolant supply device attached to an electric drilling tool and configured to supply a coolant to a drilling portion at a distal end of a drill when the drill performs drilling, the coolant supply device comprising:

• a first flange member and a second flange member provided on a rotating shaft, the rotating shaft sharing a same axis with the drill, the first flange member being positioned at the drill side, the second flange member being positioned such that the second flange member is more distant from the drill than the first flange member along the rotating shaft;
• space formed between the flange members, into which a coolant is injected;
• a coolant supply passage formed between the first flange member and the drill, the coolant supply passage guiding the coolant in the space to the drill;
• and
• a coolant push-out mechanism configured to push the coolant out of the space toward the coolant supply passage.