Not if you're satisfied with it, no.
Here's the way I look at it: Say that you're going from being a Senior Grommiteer to a Grommit Manager. While your skills as a Senior Grommiteer are important to your ability to be a Grommit Manager, there are a whole new set of skills in play, managerial skills, most of which you're pretty Junior in. You will need and expect more support from your new manager than you ever did before.
But you will grow, and gain experience in those new, softer skills, and then you will be able to demand more money than you ever could as an extremely experienced Senior Grommiteer. And if the company you're currently working for don't pay you that, you can go elsewhere.
It's very much in your interests long-term.
However, I will temper that with a word of warning: If you're going to another company, make sure that they're paying you based on your inexperience as a manager. If it is simply that they underpay everyone, you're going to have a hard time building a good team, you'll end up doing half the work yourself and still failing (because you won't have time to be a good manager), and responsibility for that will be entirely yours. ("Hey, we hired you as a manager -- you said you could do the job already.")
Your experience as a failed manager will get you nowhere in the future.