A toy gun comprising a toy gun body and a toy gun gas cartridge loading device to be attached to the toy gun body, the toy gun body comprising: a gun body coupling valve for introducing compressed gas from outside and supplying the compressed gas into the toy gun body; a loading device housing located around the gun body coupling valve; a bar-like member which is attached midway to a lateral surface of the loading device housing by a bar-like member rotating shaft for allowing an upper end and a lower end thereof to freely rotate inward of the loading device housing or outward of the loading device housing, with the upper end biased inward of the loading device housing; a gun body first lock which is located in an upper portion of the loading device housing and provided on the upper end of the bar-like member and locked with a loading device lock provided on the toy gun gas cartridge loading device when inserting a toy gun body side end portion of the toy gun gas cartridge loading device through an opening of the loading device housing for attachment to the toy gun body; and a gun body second lock which is located nearer to the lower end of the bar-like member than the bar-like member rotating shaft and lower than the gun body first lock and locked with the loading device lock provided on the toy gun gas cartridge loading device when detaching the toy gun gas cartridge loading device from the toy gun body, wherein the toy gun gas cartridge loading device houses a gas cartridge; and wherein, for attachment to the toy gun body, a toy gun side end portion of the toy gun gas cartridge loading device is housed in the loading device housing of the toy gun body; the toy gun gas cartridge loading device comprising: a loading device coupling valve which is located at a tip of the toy gun gas cartridge loading device and coupled to a gun body coupling valve of the toy gun body for attachment to the toy gun body; and a loading device lock which is located on a lateral surface thereof and locked with the gun body first lock when an end portion of the toy gun gas cartridge loading device is housed in the loading device housing of the toy gun body for attachment, and locked with the gun body second lock when detaching the toy gun gas cartridge loading device from the toy gun body. a gun body coupling valve for introducing compressed gas from outside and supplying the compressed gas into the toy gun body; a loading device housing located around the gun body coupling valve; a bar-like member which is attached midway to a lateral surface of the loading device housing by a bar-like member rotating shaft for allowing an upper end and a lower end thereof to freely rotate inward of the loading device housing or outward of the loading device housing, with the upper end biased inward of the loading device housing; a gun body first lock which is located in an upper portion of the loading device housing and provided on the upper end of the bar-like member and locked with a loading device lock provided on the toy gun gas cartridge loading device when inserting a toy gun body side end portion of the toy gun gas cartridge loading device through an opening of the loading device housing for attachment to the toy gun body; and a gun body second lock which is located nearer to the lower end of the bar-like member than the bar-like member rotating shaft and lower than the gun body first lock and locked with the loading device lock provided on the toy gun gas cartridge loading device when detaching the toy gun gas cartridge loading device from the toy gun body, wherein the toy gun gas cartridge loading device houses a gas cartridge; and wherein, for attachment to the toy gun body, a toy gun side end portion of the toy gun gas cartridge loading device is housed in the loading device housing of the toy gun body; the toy gun gas cartridge loading device comprising: a loading device coupling valve which is located at a tip of the toy gun gas cartridge loading device and coupled to a gun body coupling valve of the toy gun body for attachment to the toy gun body; and a loading device lock which is located on a lateral surface thereof and locked with the gun body first lock when an end portion of the toy gun gas cartridge loading device is housed in the loading device housing of the toy gun body for attachment, and locked with the gun body second lock when detaching the toy gun gas cartridge loading device from the toy gun body. a loading device coupling valve which is located at a tip of the toy gun gas cartridge loading device and coupled to a gun body coupling valve of the toy gun body for attachment to the toy gun body; and a loading device lock which is located on a lateral surface thereof and locked with the gun body first lock when an end portion of the toy gun gas cartridge loading device is housed in the loading device housing of the toy gun body for attachment, and locked with the gun body second lock when detaching the toy gun gas cartridge loading device from the toy gun body.