PROBLEM TO BE SOLVED: To provide a device having the following features: a hot air heater proposed by the applicants is utilized as a relay base for supplying supply CO2 and conditioned cold or hot air to a greenhouse in which a hot air heater, a carbon dioxide gas generator and a heat pump are utilized so as to create an optimal growth environment for crops in the greenhouse; a complex agricultural machine is utilized effectively; a construction of hot air heater in the machine is further developed in the invention and effectively utilized; in both of the cases where the hot air heater is operated and stopped, a passage, a fan and a duct arranged at the outlet of the passage are effectively utilized so that CO2 and mixed air is efficiently supplied to crop.SOLUTION: The invention provides a device for improving crop environment in which a hot air heater is utilized. In a greenhouse, a hot air heater, a carbon dioxide gas generator and a heat pump are arranged. Each of tubes from the carbon dioxide gas generator and heat pump is connected to an inlet port of the hot air heater. CO2 and/or hot or cold air from each of the tubes is sent to the hot air heater. A fan of the hot air heater, an inner passage and an outlet are utilized. From the duct connected to the outlet, the CO2 and/or hot or cold air is supplied to the greenhouse. Each of the machines is effectively utilized and crop environment is improved.【課題】 ハウスにおいて、温風暖房機、炭酸ガス発生機、及びヒートポンプを利用し、作物に最適な生育環境を図る装置を、本出願人が提案する、温風暖房機を中継基地として、ハウス内に、CO2供給と、冷暖気に空調された空気供給を図る。複合農業機械を有効利用する。本発明は、この文装置をさらに発展し、かつ温風暖房機の構造を有効利用する。温風暖房機の稼動時、又は停止時の何れにおいても、通路とファン、及び通路の排出口に設けられたダクトを有効利用し、効率的に、作物にCO2と、ミキシング空気を供給する。【解決手段】 本発明は、ハウスに、温風暖房機、炭酸ガス発生機、ヒートポンプを設置し、炭酸ガス発生機、及びヒートポンプの各配管を、温風暖房機の吸込口に連繋し、各配管からのCO2、及び/又は、暖冷気を、温風暖房機に送風し、温風暖房機のファン、内部通路、排出口を利用し、排出口に設けたダクトにより、ハウス内に供給可能とする温風暖房機利用の作物環境改善装置。各機械を効率的に活用し、作物環境改善が図れる。【選択図】 図1