noun
accessory case; small container for odds and ends
A small box, pouch, or compartment for holding small personal items such as jewelry, keys, or stationery.
机の上に小物入れを置いて、クリップや消しゴムを入れている。
I keep a small container on my desk for clips and erasers.
旅行のときは、アクセサリーを小物入れにまとめている。
When traveling, I keep my accessories together in a small case.
入れ物 is a general term for any container; 小物入れ specifically implies a small container for small items.
Compound of 小物 (こもの, 'small items') and 入れ (いれ, 'putting in'), from the verb 入れる (いれる, 'to put in').