I'm looking for a noun.

[peppy_man]

How do you call a person go to bed at the same time every night and get up at the same time every morning?
Is there any word or idiom which describes that kind of person?
I guess 'an early riser' is not the word, because an early riser doesn't necessarily keep regular hours... Thank you.

[Tdol]

You could say something like 'you could set your clock by him'.

[Humble]

Maybe also a pedantic person.

[curmudgeon]

A creature of habit

[BobK]

There is the expression "He kept regular hours", but this doesn'y apply exclusively to sleep patterns: He might catch the 07.25 every morning, and come home on the 17.53 - 'as regular as clockwork'.

If you want a noun, you could call him an automaton or a metronome.

b

[MikeNewYork]

Maybe also a pedantic person.

I wouldn't use "pedantic" for this use.

[MikeNewYork]

How do you call a person go to bed at the same time every night and get up at the same time every morning?
Is there any word or idiom which describes that kind of person?
I guess 'an early riser' is not the word, because an early riser doesn't necessarily keep regular hours... Thank you.

I think "creature of habit" is great. You could also say:

regimented person