How to say "apparatus" in Japanese

• 道具どうぐJLPT N4approx.Common
  nounCovers the everyday sense of apparatus as a tool, implement or utensil for doing a task. It suits general, hands-on items rather than technical equipment, so for laboratory or mechanical apparatus another word usually fits better.
  この道具どうぐはなんの役やくにもたたない。↗

  This tool is good for nothing.
• 装置そうちJLPT N3approx.Common
  noun, suru verb, transitive verbThe closest match for apparatus as a technical device or installation built for a specific function. Typical contexts include laboratory, industrial and electronic apparatus.
  この暖房だんぼう装置そうちは石油せきゆを燃料ねんりょうとする。↗

  This heating system burns oil.
• 機器ききCommon
  nounRefers to devices and equipment, especially machinery or instruments as units of apparatus, often in technical or office settings. A good choice when the apparatus is a piece of functional equipment.
  ディスプレイはモニタともいい、コンピュータなどの機器ききから出力しゅつりょくされる静止画せいしがまたは動画どうがの映像えいぞう信号しんごうを表示ひょうじする機器ききである。↗

  A display, aka monitor, is an appliance that displays video signal of still images and moving pictures produced by a computer or similar device.
• 器具きぐJLPT N2approx.Common
  nounMeans utensil, implement, tool or instrument — apparatus in the sense of a set of implements for a purpose, such as instruments used in a craft, sport, or kitchen. Less apt for large mechanical apparatus.
  これは主婦しゅふの手間てまを省はぶく便利べんりな器具きぐです。↗

  This is a great time-saving gadget for the housewife.
• 機械きかいJLPT N3approx.Common
  nounReally means machine or appliance, and its apparatus gloss applies only when the apparatus is machine-like. For non-mechanical apparatus it is seldom the word you want.
  血圧計けつあつけいが大切たいせつな検査けんさ器械きかいです。↗

  The sphygmomanometer is an important diagnostic instrument.

For the technical sense of 'apparatus' choose 装置 or 機器, for tools and implements 道具 or 器具, and 機械 only when the apparatus is machine-like equipment.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

• 道具どうぐtool
• 装置そうちequipment
• 機器ききdevice
• 器具きぐutensil
• 器具類きぐるいinstruments
• 機械きかいinstrument