To maintain a proper soil water state, to uniformly supply water to the whole field, not to make the field excessively wet even if watered too much and to readily carry out heat sterilization by solar heat, etc. in a crop cultivation apparatus for cultivating crops such as tomato, cucumber, etc.

A substrate 2 having a U-shaped cross-section is arranged on soil 4 in a greenhouse and a waterproof sheet 12 is laid on the substrate 2. A bottom watering mat 3 comprising a nonwoven fabric is laid on the waterproof sheet and a pair of plate frames 5 are stood on the bottom watering mat 3 to form a culture space 13. A water tube 6 is piped on the bottom of the water mat 3. Cultivation soil 8 is packed into the culture space 13. Consequently, water sprinkled from the watering tube 6 is diffused to the whole bottom watering mat 8, uniformly retained and gradually watered in a form of rising from the bottom by the capillary action of the cultivation soil 8.