The bank said it hoped to raise £75m "to support the medium-term growth of the business".
In its H1 results the bank said its pre-tax profit for the six months to the end of June was £18.6m, a 249% increase on the £5.3m it made in the same period a year ago.
Chief Executive Phillip Monks said:
"Now in our sixth year of growth, becoming a public company is the natural next step in Aldermore's evolution and positions us for the next stage of our development."
The public offering is being co-ordinated by Credit Suisse and Deutsche Bank, while Nomura and Numis have been named as co-lead managers and Lazard is financial adviser.