Developing device and image forming apparatus

Developing device supplying developer to developing roller, while causing developer to circulate in passage including first and second conveying passages in parallel, and while ejecting part of developer to outside via ejection passage formed as extension of first conveying passage on downstream side in developer conveying direction, developing roller being provided along first conveying passage. Developing device includes: first communication path provided as branch of first conveying passage on downstream side, allowing first passage to communicate with second passage; first conveying part conveying developer in first passage toward first communication path; and entrance allowance unit allowing developer to enter ejection passage from first passage depending on pressure of developer in first passage, first conveying part including main and sub-conveying parts, main conveying part being provided in region corresponding to roller, sub-conveying part, provided downstream of main conveying part, conveying smaller amount of developer per unit time than main conveying part.